SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
             ----------------------------------------------------

                                 FORM 10-K

(mark one)
[ X ] Annual Report Pursuant to Section 13 or 15(d) of the Securities
      Exchange Act of 1934 for the fiscal year ended January 1, 2000

[   ] Transition Report Pursuant to Section 13 or 15(d) of the Securities
      Exchange Act of 1934

                          Commission file number 1-9567

                                 THERMEDICS INC.
             (Exact name of Registrant as specified in its charter)

Massachusetts                                   04-2788806
(State or other jurisdiction of
incorporation or organization)       (I.R.S. Employer Identification No.)

470 Wildwood Street, P.O. Box 2999
Woburn, Massachusetts                                    01888-1799
(Address of principal executive offices)                 (Zip Code)

            Registrant's telephone number, including area code: (781) 622-1000

            Securities registered pursuant to Section 12(b) of the Act:

     Title of each class         Name of each exchange on which registered
 Common Stock, $.10 par value              American Stock Exchange

            Securities registered pursuant to Section 12 (g) of the Act:
                                      None

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months, and (2) has been subject to the filing requirements for
at least the past 90 days. Yes [ X ] No [ ]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of the Registrant's knowledge, in definitive proxy or information
statements incorporated by reference into Part III of this Form 10-K or any
amendment to this Form 10-K. [ ]

The aggregate market value of the voting stock held by nonaffiliates of the
Registrant as of January 28, 2000, was approximately $61,227,000.

As of January 28, 2000, the Registrant had 41,945,661 shares of common stock
outstanding.

                       DOCUMENTS INCORPORATED BY REFERENCE

The information required by Part III of Form 10-K will be filed as part of an
amendment to this Form 10-K no later than 120 days after January 1, 2000, and
such information is incorporated by reference from such filing.

                                     PART I

Item 1.  Business

(a)   General Development of Business

      The continuing operations of Thermedics Inc. (the Company or the
Registrant) operate in three reportable segments:  Quality Assurance and
Security Products, Precision Weighing and Inspection Equipment, and Respiratory
Care Products.

      The Quality Assurance and Security Products segment consists of the
Company's Thermedics Detection Inc. subsidiary, which develops, manufactures,
and markets high-speed detection and measurement instruments used in a variety
of on-line industrial process applications, security applications, and
laboratory analyses.

      The Company's Precision Weighing and Inspection Equipment segment includes
the Company's Thermo Sentron Inc. subsidiary, which develops, manufactures, and
markets high-speed precision-weighing and inspection equipment for industrial
production and packaging lines.

      The Respiratory Care Products segment consists of Erich Jaeger GmbH, which
was acquired by the Company in July 1999. Jaeger, based in Germany, develops and
manufactures equipment for lung-function, cardio respiratory, and sleep disorder
diagnosis and monitoring.

      In addition, the Company develops and manufactures enteral
nutrition-delivery systems and a line of medical-grade polymers used in medical
disposables and in nonmedical, industrial applications, including safety glass
and automotive coatings.

      In May 1999, the Company announced its intention to sell its Thermo Voltek
Corp. subsidiary, which represents its former Power Electronics and Test
Equipment segment. In January 2000, Thermo Electron Corporation announced a
reorganization plan under which the Company intends to sell its Thermo
Cardiosystems Inc. subsidiary, which represents its former Heart Assist and
Blood Testing Devices segment. The Company expects to complete the sale of the
Power Electronics and Test Equipment businesses in the first half of 2000 and
expects to complete the sale of Thermo Cardiosystems during 2000. The results of
these businesses have been presented as discontinued operations in the
accompanying financial statements. Except where indicated, the information
presented in this Form 10-K pertains to the Company's continuing operations.

      The Company was incorporated in 1983 under the laws of Massachusetts as a
wholly owned subsidiary of Thermo Electron. Thermo Electron has announced a
proposed reorganization involving certain of Thermo Electron's subsidiaries,
including the Company. Under this plan, the Company has made cash tender offers
of $15.50 per share for Thermo Sentron and $8.00 per share for Thermedics
Detection in order to bring its equity ownership in each of these companies,
when combined with Thermo Electron's equity interest in each, to at least 90%.
As of January 1, 2000, the Company owned approximately 74.2% of Thermo Sentron
and 83.6% of Thermedics Detection, respectively, and Thermo Electron owned
approximately 12.4% of Thermo Sentron and 5.3% of Thermedics Detection,
respectively. If these tender offers are successful, each of these companies
would then be taken private by the Company through a short-form merger at the
same cash prices as the tender offers. Thermo Electron also intends to take the
Company private. Thermo Electron has announced that it will conduct an exchange
offer for any and all of the outstanding shares of Company common stock held by
public shareholders. In the exchange offer, holders of Company common stock
would receive shares of Thermo Electron common stock in exchange for each of
their shares of the Company. On March 8, 2000, Thermo Electron announced the
proposed exchange ratio of 0.45 shares of Thermo Electron common stock for each
share of Company common stock. Thermo Electron will condition the exchange offer
on receiving acceptances from holders of enough shares so that, when combined
with its current share ownership, Thermo Electron's ownership reaches at least
90%. If Thermo Electron achieves this 90% ownership threshold, it would acquire
all remaining outstanding shares of the Company through a short-form merger. In
the short-form merger, minority shareholders who do not participate in the
exchange offer would also receive shares of Thermo Electron common stock in
exchange for their Company common stock at the same ratio. As of January 1,

                                       2

2000, Thermo Electron owned 31,759,424 shares of the Company's common stock,
representing 76% of such stock outstanding. The proposed transactions are
subject to a number of conditions, as outlined in Note 16 to Consolidated
Financial Statements in the Registrant's 1999* Annual Report to Shareholders,
which information is incorporated herein by reference.

      Thermo Electron develops, manufactures, and sells measurement and
detection instruments used in virtually every industry to monitor, collect, and
analyze data that provide knowledge for the user. For example, Thermo Electron's
powerful analysis technologies help researchers sift through data to make the
discoveries that will fight disease or prolong life; allow manufacturers to
fabricate ever-smaller components required to increase the speed and quality of
communications; or monitor and control industrial processes on-line to ensure
that critical quality standards are met efficiently and safely.

      During 1999, Thermo Electron purchased 919,700 shares of the Company's
common stock in the open market for $5.9 million. Additionally, during 1999,
Thermo Electron purchased in the open market 147,500 shares of common stock of
Thermedics Detection for $1.3 million and 41,700 shares of common stock of
Thermo Sentron for $0.4 million.

Forward-looking Statements

      Forward-looking statements, within the meaning of Section 21E of the
Securities Exchange Act of 1934, are made throughout this Annual Report on Form
10-K. For this purpose, any statements contained herein that are not statements
of historical fact may be deemed to be forward-looking statements. Without
limiting the foregoing, the words "believes," "anticipates," "plans," "expects,"
"seeks," "estimates," and similar expressions are intended to identify
forward-looking statements. There are a number of important factors that could
cause the results of the Company to differ materially from those indicated by
such forward-looking statements, including those detailed under the heading
"Forward-looking Statements" in the Registrant's 1999 Annual Report to
Shareholders, which statements are incorporated herein by reference.

(b)   Financial Information About Segments

      Financial information concerning the Company's segments is summarized in
Note 12 to Consolidated Financial Statements in the Registrant's 1999 Annual
Report to Shareholders, which information is incorporated herein by reference.

(c)   Description of Business

      (i)           Principal Products and Services

Quality Assurance and Security Products

Detection Instruments

      Thermedics Detection supplies high-speed detection and measurement systems
to examine a variety of products and substances either on-line or in a
laboratory to ensure their quality. The ALEXUS(R) systems detect trace amounts
of constituents that would affect product quality in refillable plastic
containers of soft drinks, water, and other beverages. The InScan(R) high-speed
X-ray imaging system uses high-speed X-ray imaging technology to determine
accurate fill volume, net volume, proper contents, and package integrity of
containers for the beverage, food, and other industries. Through its Moisture
Systems division, Thermedics Detection designs, manufactures, and markets
- --------------------
*  References to 1999, 1998, and 1997 herein are for the fiscal years ended
   January 1, 2000, January 2, 1999, and January 3, 1998, respectively.


                                       3

equipment that uses near-infrared spectroscopy to measure moisture and other
product constituents, including fats, proteins, oils, flavorings, solvents,
adhesives, and coatings, in a variety of products as they move along
manufacturing lines. These systems are used across the food, pharmaceutical,
chemical, petrochemical, tobacco, forest products, paper converting, plastics,
textiles, corrugating, and other industries.

      Thermedics Detection's high-speed gas chromatograph, called Flash-GC(TM),
provides information on the composition of a wide range of substances, such as
pharmaceuticals, food, and water, at speeds 20 to 50 times faster than
conventional gas chromatography, while its EZ-Flash(TM) system is an upgrade kit
that can be added to virtually any conventional gas chromatograph to conduct
chemical analyses up to 30 times faster.

      Also through Thermedics Detection, the Company produces security
instruments that use trace particle- and vapor-detection techniques for
forensics and search and screening applications under the direction of police,
border police, transportation authorities, and carriers. Thermedics Detection's
principal security instrument is the EGIS(R) system, a highly sensitive
particle- and vapor-detection system for screening baggage, packages, freight,
and electronic equipment, such as personal computers, for the presence of a wide
range of explosives, including plastic explosives that have proven difficult to
detect using conventional methods. Currently, more than 275 EGIS units are
deployed at airports, border crossings, and other checkpoints. In addition, EGIS
units have been used in highly visible forensic investigations, including the
crash of TWA Flight 800, as well as the bombings in Oklahoma City, at New York's
World Trade Center, and at locations in Israel, Buenos Aries, and the United
Kingdom. In 1998, Thermedics Detection introduced a new line of benchtop
explosives-detection systems based on its EGIS technology. This family of
products includes the EGIS II, the more sensitive EGIS III, and the EGIS IV,
Thermedics Detection's most sensitive explosives detector to date. Thermedics
Detection also has developed SecurScan(TM), a walk-through explosives detector.

      During 1999, 1998, and 1997, the Company derived revenues of $26.4
million, $40.3 million, and $51.3 million, respectively, from its detection
instruments.

Laboratory Products

      Through its Orion subsidiary, Thermedics Detection manufactures a wide
range of electrochemistry products that determine the quality of many substances
by measuring their pH, specific ion concentration, dissolved oxygen, and
conductivity. Orion's products are used in the food, beverage, pharmaceutical,
chemical, environmental analysis, drinking water, wastewater treatment,
agricultural, biomedical research, and many other industries. Pure water
monitors, also marketed under the Orion name, use ion-selective technology to
evaluate water quality in the power, semiconductor, petrochemical, and paper
industries. Other products include microweighing equipment and titration
systems.

      During 1999, 1998, and 1997, the Company derived revenues of $47.2
million, $51.3 million, and $53.1 million, respectively, from its laboratory
products.

Precision Weighing and Inspection Equipment

      Thermo Sentron serves two principal markets: packaged goods and bulk
materials. Thermo Sentron's products for the packaged-goods market include a
broad line of checkweighing equipment and metal detectors that can be integrated
at various points in production lines for process control and quality assurance.
Thermo Sentron also produces hot foil and thermal printers and X-ray inspection
equipment. Thermo Sentron's packaged-goods customers include companies in the
food-processing, pharmaceutical, mail-order, and other diverse industries.
Products in Thermo Sentron's bulk-materials line include conveyor-belt scales,
solid level-measurement and conveyor-monitoring systems, sampling systems, and
small-capacity feeders. These products are sold primarily to customers in the
mining and material-processing industries, as well as electric utilities and
chemical and other manufacturing companies. In June 1998, Thermo Sentron
acquired the three businesses that constituted the product-monitoring group of
Graseby

                                       4

Limited (the product-monitoring businesses), a subsidiary of Smiths Industries
plc. The product-monitoring businesses design, manufacture, and distribute
specialized packaged-goods equipment, including checkweighers and metal
detectors, for the food and pharmaceutical industries.

Respiratory Care Products

      Jaeger develops and manufactures state-of-the-art diagnostic and
monitoring tools for specialized use in pulmonology, as well as cardiology,
sleep, and neurology. Jaeger is a worldwide leader in the pulmonary diagnostic
market and offers a full line of PC-based diagnostic products to perform fully
automated testing of spirometry, lung volume, lung diffusing capacity, and
airways resistance in both adults and children. These products are used at
hospitals, clinics, and private medical practices. In addition, Jaeger offers
pulmonary function labs - sophisticated, hospital-based systems that are used to
measure complete lung function. Jaeger's cardiorespiratory diagnostic systems,
which include treadmills and electrocardiograph systems, help measure a
patient's metabolic function to assist in the diagnosis of cardiopulmonary
disease and aid in the rehabilitation of patients who are suffering from heart
or lung disease. Jaeger's electrophysiology products are used in hospitals and
physicians offices to monitor and diagnose neurological function. Jaeger's sleep
diagnostic and monitoring equipment is typically used in sleep labs. Sleep
disorders include sleep apnea, insomnia, parasomnia, and narcolepsy. Jaeger has
also introduced a product for the growing home-based testing market. In
addition, Jaeger has expanded the use of computer technology as part of a
patient's disease management process. Jaeger is building on its current product
software platform, LAB, which offers physicians, throughout all levels of care,
the tools necessary to decrease the time it takes to perform tests and provide
therapy.

Other

      The Company's research relating principally to the development of its LVAS
has resulted in the development of proprietary medical-grade plastics marketed
under the names Tecoflex(R) and Tecothane(R). Tecoflex and Tecothane are
thermoplastic polyurethanes used in medical disposables and industrial products.
The Company sells Tecoflex and Tecothane in bulk form for fabrication by the
customer, and also extrudes precision tubing to customer specifications.

      The Company's CORPAK MedSystems subsidiary designs, manufactures, and
markets enteral feeding systems that introduce special nutritional solutions
into the stomach or the small intestine through tubes entering the nose or
stomach. Enteral therapy is used for patients who are unable to feed themselves
but who do not require parenteral (intravenous) feeding. CORPAK's products
include bags for nutritional fluids, delivery pumps, associated pump sets that
hook up to the pumps, and feeding tubes. In addition, CORPAK markets catheters
for peritoneal dialysis.

Discontinued Operations

      The Company's discontinued operations consist of the Company's former
Power Electronics and Test Equipment and Heart Assist and Blood Testing Devices
segments. The Power Electronics and Test Equipment segment, through Thermo
Voltek, designs, manufactures, and markets a range of products related to power
amplification, conversion, and quality and electronics-test instruments.

      The Heart Assist and Blood Testing Devices segment consists of Thermo
Cardiosystems, which has developed two implantable left ventricular-assist
systems (LVAS): a pneumatic, or air-driven, system and an electric version.
Thermo Cardiosystems' International Technidyne Corporation subsidiary is a
leading manufacturer of near-patient, whole-blood coagulation testing equipment
and related disposables and also manufactures premium-quality, single-use
skin-incision devices.



                                       5

      (ii) and (xi) New Products; Research and Development

      The Company maintains a research and development capability to support its
existing products and to develop new products. A number of programs are
underway, funded by the Company solely or jointly with an outside source. These
programs include development of new products, quality assurance and security
instruments; and respiratory, diagnostic, and monitoring instruments. The
Company also develops new grades of polymers to meet specific customer
requirements for industrial and medical applications.

      During 1999, 1998, and 1997, the Company expended $14.3 million, $12.9
million, and $12.0 million, respectively, on internally sponsored research and
development programs, and $1.8 million, $2.3 million, and $1.1 million,
respectively, on research and development programs sponsored by others. As of
January 1, 2000, 165 professional employees were engaged full-time in research
and development activities.

      (iii)         Raw Materials

      Continuing Operations

      Supplies purchased by the Company are available from a number of different
suppliers or from alternative sources that could be developed without a material
adverse effect on the Company's business. To date, the Company has experienced
no difficulties in obtaining these materials.

      Discontinued Operations

      Certain raw materials used in the manufacture of Thermo Cardiosystems'
LVAS are available from only one or two suppliers. Thermo Cardiosystems is
making efforts to minimize the risks associated with sole sources and ensure
long-term availability, including qualifying alternative materials and
components or developing alternative sources for materials and components
supplied by a single source. Although Thermo Cardiosystems believes that it has
adequate supplies of materials and components to meet demand for the LVAS for
the foreseeable future, no assurance can be given that Thermo Cardiosystems will
not experience shortages of certain materials or components in the future that
could delay shipments of the LVAS.

      The cost to Thermo Cardiosystems to evaluate and test alternative
materials and components and the time necessary to obtain FDA approval for these
materials and components are inherently difficult to determine because both time
and cost are dependent on at least two factors: the similarity of alternative
materials or components to the original materials or components, and the amount
of third-party testing that may have already been completed on alternative
materials or components. There can be no assurance that the substitution of
alternative materials or components will not cause delays in Thermo
Cardiosystems' LVAS development program or adversely affect Thermo
Cardiosystems' ability to manufacture and ship LVAS to meet demand.

      (iv)          Patents, Licenses, and Trademarks

      Continuing Operations

      The Company considers its intellectual property important in the operation
and growth of its business, and its policy is to protect this property through
patents, license and confidentiality agreements, trademarks, and trade secret
protection. The Company applies for and maintains patents in the U.S. and in
foreign countries, particularly in the areas of biomedical materials, medical
products, and analytical instruments. Although some of these patent rights may
provide the Company with a competitive advantage, the Company primarily relies
on its know-how and trade secrets. In addition, there can be no assurance that
third parties will not assert claims against the Company that the Company
infringes the intellectual property rights of such parties. The Company could
incur substantial costs and diversion of management resources with respect to
the defense of any such claims, which could have a material adverse effect on


                                       6

the Company's business, financial condition, and results of operations.
Furthermore, parties making such claims could secure a judgment awarding
substantial damages, as well as injunctive or other equitable relief, which
could effectively block the Company's ability to make, use, sell, distribute, or
market its products and services in the U.S. or abroad. In the event that a
claim relating to intellectual property is asserted against the Company, the
Company may seek licenses to such intellectual property. There can be no
assurance, however, that such licenses could be obtained on commercially
reasonable terms, if at all. The failure to obtain the necessary licenses or
other rights could preclude the sale, manufacture, or distribution of the
Company's products and, therefore, could have a material adverse effect on the
Company's business, financial condition, and results of operations.

      The Company has certain licenses to the technology resulting from its
customer-sponsored development of the ALEXUS system. The Company's patents and
agreements have varying lives ranging from one year to approximately 20 years,
and the Company does not believe that the expiration or termination of any one
of these patents or agreements would materially affect the Company's business.

      Discontinued Operations

      Thermo Cardiosystems has received correspondence from a third party
alleging that the textured surface of the LVAS housing infringes certain patent
rights of such third party. In general, an owner of intellectual property can
prevent others from using such property without a license and is entitled to
damages for unauthorized usage. Thermo Cardiosystems has investigated the bases
of the allegation and, based on the opinion of its counsel and the Company's
assessment of the proceedings in the United States Patent and Trademark Office
to date, it believes that if it were sued on these bases, it would have
meritorious defenses. Given the inherent uncertainties in dispute resolution,
however, if Thermo Cardiosystems were sued and the outcome were unfavorable,
Thermo Cardiosystems' results of operations or financial condition could be
materially adversely affected in amounts Thermo Cardiosystems cannot reasonably
estimate.

      In August 1998, Thermo Cardiosystems obtained an exclusive license to
incorporate technology developed by Sulzer Electronics Ltd. into an advanced
version of Thermo Cardiosystems' LVAS, HeartMate III. Sulzer Electronics Ltd.,
based in Switzerland, is a company within the Sulzer Corporation. HeartMate III
is a miniature centrifugal pump featuring a magnetically controlled system that
has been developed by Sulzer Electronics' Magnetics Group.

      (v)           Seasonal Influences

      There are no significant seasonal influences on the Company's sales of its
products.

      (vi)          Working Capital Requirements

      There are no special inventory requirements or credit terms extended to
customers that would have a material adverse effect on the Company's working
capital.

      (vii)         Dependency on a Single Customer

      No single customer accounted for more than 10% of the Company's total
revenues in any of the past three years.

                                       7

      (viii)        Backlog

      The Company's backlog of firm orders was as follows:



                                                                                               
(In thousands)                                                                              1999     1998
- ---------------------------------------------------------------------------------------- -------  -------

Quality Assurance and Security Products                                                  $ 4,601  $ 6,065
Precision Weighing and Inspection Equipment                                               10,505   14,683
Respiratory Care Products                                                                  5,192        -
Other                                                                                      1,776    1,843
                                                                                         -------  -------

                                                                                         $22,074  $22,591
                                                                                         =======  =======
      Certain of these orders are cancelable by the customer upon payment of a
cancellation charge. The Company anticipates that substantially all of the
backlog at January 1, 2000, will be shipped or completed during the next twelve
months. The decrease in backlog from existing businesses primarily resulted from
a decrease in demand at the Company's Quality Assurance and Security Products
and Precision Weighing and Inspection Equipment segments.

      (ix)          Government Contracts

      Not applicable.

      (x)           Competition

Quality Assurance and Security Products

      The Company's quality assurance products compete with systems manufactured
by numerous companies. The Company believes, however, that these companies are
generally focused on particular niches in the process detection systems market,
only in some of which the Company competes. Competition in the markets for each
of the Company's quality assurance systems is based primarily on performance,
durability, service and, to a lesser extent, price. The Company believes that
its systems' performance and speed, as well as the Company's reputation for
developing superior new technologies and for the innovative application of
existing technologies to a variety of high-speed production environments and
product quality-assurance problems, are competitive advantages.

      In the security instrument market, the Company competes with a small
number of companies, including other makers of chemical trace detection
instruments, and, to a lesser degree, makers of enhanced X-ray detectors.
Competition in this market is based primarily on performance, including speed,
accuracy, and the range of explosives that can be detected; ease of use;
service; and price. The Company's principal competitor in the trace detection
market is Barringer Technologies Inc., a Canadian firm that has placed several
trace detectors in airports.

      In the laboratory products market, the Company competes with several
international companies. The Company competes on the basis of performance,
service, technology, and price. Competitors include Corning, Fisher Scientific,
Mettler-Toledo AG, and Beckman Coulter.

                                       8

Precision Weighing and Inspection Equipment

      The Company's Thermo Sentron subsidiary encounters and expects to continue
to encounter intense competition in the sale of its products. Thermo Sentron's
principal competitors in the packaged-goods market are Ishida Scales Mfg. Co.,
Ltd. and Mettler-Toledo AG. In the more fragmented bulk-materials market, Thermo
Sentron competes on a worldwide basis primarily with Carl Schenck AG and
Milltronics Corporation. Thermo Sentron believes that the principal competitive
pressures affecting the market for precision-weighing and inspection equipment
include customer service and support, quality and reliability, price, accuracy,
ease of use, distribution channels, technical features, compatibility with
customers' manufacturing processes, and regulatory approvals.

Respiratory Care Products

      The Company is a leading supplier of respiratory-care and other products.
Numerous companies compete in this market worldwide. In the market for lung
function diagnostic products, Jaeger competes with Medical Graphics,
Collins/Ferraris, and CosMed, among others. The cardiorespiratory diagnostic
products compete with products offered by companies such as Dantec/Medtronic,
Medelec, and Nihon Kohden. In the sleep diagnostic market, Jaeger competes with
Respironcs, ResMed, and NPB, among others. Competition in all of these markets
is based primarily upon product features, reliability, services, product
reputation, and price.

Other

      In the market for medical-grade polymers and enteral nutrition-delivery
systems, the Company competes primarily with large pharmaceutical,
medical-device, and chemical companies, many of which have substantially greater
financial, technical, and human resources than those of the Company. Competition
within these markets is intense, and is based primarily on price, efficacy, and
technological advances.

      (xii)         Environmental Protection Regulations

      The Company believes that compliance by the Company with federal, state,
and local environmental protection regulations will not have a material adverse
effect on its capital expenditures, earnings, or competitive position.

      (xiii)        Number of Employees

      As of January 1, 2000, the Company's continuing operations employed 1,613
people and its discontinued operations employed 687 people.

(d)   Financial Information About Geographic Areas

      Financial information about geographic areas is summarized in Note 12 to
Consolidated Financial Statements in the Registrant's 1999 Annual Report to
Shareholders, which information is incorporated herein by reference.


(e)   Executive Officers of the Registrant


                         
        Name                Age   Present Title (Fiscal Year First Became Executive Officer)
        ------------------  ---   ---------------------------------------------------------

        John T. Keiser      64    President and Chief Executive Officer (1998)
        Victor L. Poirier   58    Senior Vice President (1983)
        Theo Melas-Kyriazi  40    Chief Financial Officer (1998)
        Paul F. Kelleher    57    Chief Accounting Officer (1985)


                                       9

      Each executive officer serves until his successor is chosen or appointed
and qualified, or until earlier resignation, death, or removal. All executive
officers, except Messrs. Keiser and Melas-Kyriazi, have held comparable
positions for at least five years, either with the Company or with its parent
company, Thermo Electron. Mr. Melas-Kyriazi was appointed Chief Financial
Officer of the Company and Thermo Electron on January 1, 1999. He joined Thermo
Electron in 1986 as Assistant Treasurer, and became Treasurer in 1988. In 1994,
he was named President and Chief Executive Officer of Thermo Spectra
Corporation, a public subsidiary of Thermo Instrument. In 1998, he became Vice
President of Corporate Strategy for Thermo Electron. He remains a Vice President
of Thermo Electron. Mr. Keiser was appointed Senior Vice President of the
Company in 1994. At the same time, he was named President of Thermo Biomedical,
a newly created subsidiary of Thermo Electron. He was named President and Chief
Executive Officer of the Company in March and December 1998, respectively. Mr.
Keiser was appointed Chief Operating Officer, Biomedical and Advanced
Technology, of Thermo Electron in September 1998 and his title was changed to
Chief Operating Officer, Biomedical, in March 1999. From 1985 until 1994, he was
President of the Eberline Instrument division of Thermo Instrument Systems Inc.,
a majority-owned public subsidiary of Thermo Electron. Messrs. Keiser,
Melas-Kyriazi, and Kelleher are full-time employees of Thermo Electron, and Mr.
Poirier is a full-time employee of Thermo Cardiosystems, but they devote such
time to the affairs of the Company as the Company's needs reasonably require.

Item 2.  Properties

      The Company believes that its facilities are in good condition and are
adequate to meet its current needs and that other suitable space is readily
available if any leases are not extended. The location and general character of
the Company's properties by industry segment as of January 1, 2000, are as
follows:

Quality Assurance and Security Products

      The Quality Assurance and Security Products segment operates from two
principal facilities: an 111,000-square foot office, research and development,
and manufacturing facility in Massachusetts occupied under a lease expiring in
2006, subject to one five-year renewal option at the election of the Company;
and a 115,000-square foot office and manufacturing facility in Massachusetts,
occupied under a lease expiring in 2006. The Company also leases approximately
9,000 square feet in Enschede, Holland, occupied under a lease expiring in 2001.
In addition, the Company leases approximately 33,200 square feet of office space
throughout the world for its sales and service operations, and owns
approximately 14,300 square feet of manufacturing, office, and storage
facilities in Scotland.

Precision Weighing and Inspection Equipment

      The Precision Weighing and Inspection Equipment segment leases
approximately 314,300 square feet of office, engineering, and manufacturing
space principally in Minnesota, the United Kingdom, Australia, and Germany under
leases expiring at various dates through 2068.

Respiratory Care Products

      The Respiratory Care Products segment leases approximately 124,900 square
feet of office, engineering, and manufacturing space, principally in Germany,
under leases expiring at various dates through 2004.

Other

      The Company also leases approximately 131,000 square feet of office,
engineering, laboratory, and manufacturing space in Massachusetts and Illinois,
under leases expiring at various dates through 2004.

                                       10

Discontinued Operations

      The Company's discontinued operations own approximately 62,000 square feet
of office, engineering, laboratory, and manufacturing space in New Jersey and
lease approximately 185,000 square feet of office, engineering, laboratory, and
manufacturing space in Massachusetts, New Jersey, Washington, California, and
the United Kingdom.

Item 3.  Legal Proceedings

      Not applicable.

Item 4.  Submission of Matters to a Vote of Security Holders

      Not applicable.

                                     PART II

Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

      Information concerning the market and market price for the Registrant's
Common Stock, $.10 par value, and dividend policy is included under the sections
labeled "Common Stock Market Information" and "Dividend Policy" in the
Registrant's 1999 Annual Report to Shareholders and is incorporated herein by
reference.

Item 6.  Selected Financial Data

      The information required under this item is included under the sections
labeled "Selected Financial Information" and "Dividend Policy" in the
Registrant's 1999 Annual Report to Shareholders and is incorporated herein by
reference.

Item 7.  Management's Discussion and Analysis of Financial Condition and Results
         of Operations

      The information required under this item is included under the heading
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's 1999 Annual Report to Shareholders and is
incorporated herein by reference.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

      The information required under this item is included under the heading
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" in the Registrant's 1999 Annual Report to Shareholders and is
incorporated herein by reference.

Item 8.  Financial Statements and Supplementary Data

      The Registrant's Consolidated Financial Statements as of January 1, 2000,
and Supplementary Data are included in the Registrant's 1999 Annual Report to
Shareholders and are incorporated herein by reference.

Item 9.  Changes in and Disagreements with Public Accountants on Accounting and
         Financial Disclosure

      Not applicable.

                                    PART III

      The information required under Items 10, 11, 12, and 13 of Form 10-K will
be filed as part of an amendment to this Form 10-K no later than 120 days after
January 1, 2000, the end of the Registrant's fiscal year covered by this Form
10-K.


                                       11

                                     PART IV

Item 14.  Exhibits, Financial Statement Schedules, and Reports on Form 8-K

(a,d)  Financial Statements and Schedules.

       (1)The consolidated financial statements set forth in the list below are
          filed as part of this Report.

       (2)The consolidated financial statement schedule set forth in the list
          below is filed as part of this Report.

       (3)Exhibits filed herewith or incorporated herein by reference are set
          forth in Item 14(c) below.

       List of Financial Statements and Schedules Referenced in this Item 14

       Information incorporated by reference from Exhibit 13 filed herewith:

          Consolidated Statement of Operations
          Consolidated Balance Sheet
          Consolidated Statement of Cash Flows
          Consolidated Statement of Comprehensive Income and Shareholders'
               Investment
          Notes to Consolidated Financial Statements
          Report of Independent Public Accountants

       Financial Statement Schedules filed herewith:

          Schedule II:  Valuation and Qualifying Accounts

       All other schedules are omitted because they are not applicable or not
       required, or because the required information is shown either in the
       financial statements or in the notes thereto.

(b)    Reports on Form 8-K

       None.

(c)    Exhibits

       See Exhibit Index on the page immediately preceding exhibits.



                                       12

                                   SIGNATURES

      Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed by
the undersigned, thereunto duly authorized.

Date:  March 23, 2000                  THERMEDICS INC.


                                       By: /s/ John T. Keiser
                                           John T. Keiser
                                           President and Chief Executive Officer

      Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
Registrant and in the capacities indicated, as of March 23, 2000.

Signature                              Title


By:  /s/ John T. Keiser                President, Chief Executive Officer, and Director
     John T. Keiser

By:  /s/ Theo Melas-Kyriazi            Chief Financial Officer
     Theo Melas-Kyriazi

By:  /s/ Paul F. Kelleher              Chief Accounting Officer
     Paul F. Kelleher

By:  /s/ T. Anthony Brooks             Director
     T. Anthony Brooks

By:  /s/ Peter O. Crisp                Director
     Peter O. Crisp

By:  /s/ Paul F. Ferrari               Director
     Paul F. Ferrari

By:  /s/ George N. Hatsopoulos         Director
     George N. Hatsopoulos

By:  /s/ John W. Wood Jr.              Chairman of the Board and Director
     John W. Wood Jr.

By:  /s/ Nicholas T. Zervas            Director
     Nicholas T. Zervas



                                       13


                    Report of Independent Public Accountants

To the Shareholders and Board of Directors of Thermedics Inc.:

      We have audited, in accordance with generally accepted auditing standards,
the consolidated financial statements included in Thermedics Inc.'s Annual
Report to Shareholders incorporated by reference in this Form 10-K, and have
issued our report thereon dated February 10, 2000 (except with respect to the
matters discussed in Note 16, as to which the date is March 8, 2000). Our audits
were made for the purpose of forming an opinion on those statements taken as a
whole. The schedule listed in Item 14 on page 12 is the responsibility of the
Company's management and is presented for purposes of complying with the
Securities and Exchange Commission's rules and is not part of the basic
consolidated financial statements. The schedule has been subjected to the
auditing procedures applied in the audits of the basic consolidated financial
statements and, in our opinion, fairly states in all material respects the
consolidated financial data required to be set forth therein in relation to the
basic consolidated financial statements taken as a whole.



                                                      Arthur Andersen LLP



Boston, Massachusetts
February 10, 2000


                                       14

SCHEDULE II

                                 THERMEDICS INC.
                        Valuation and Qualifying Accounts
                                 (In thousands)


                                                                                   
                                                      Provision      Accounts                     Balance
                                      Balance at     Charged to       Written                      at End
                                       Beginning        Expense           Off                     of Year
Description                              of Year                                  Other (a)
- -------------------------------       ----------     ----------      --------     ---------       -------

Allowance for Doubtful Accounts

Year Ended January 1, 2000                $2,850        $ 1,795        $  (511)      $  775       $ 4,909

Year Ended January 2, 1999                $2,574        $   610        $(1,267)      $  933       $ 2,850

Year Ended January 3, 1998                $3,580        $   369        $(1,257)      $ (118)      $ 2,574


                                                         Amount                                   Balance
                                      Balance at    Capitalized                                    at End
                                       Beginning     as Cost of                                   of Year
Description                              of Year    Acquisition  Expenditures     Other (d)
- --------------------------------      ----------    -----------  ------------     ---------       -------

Accrued Acquisition Reserves (b)

Year Ended January 1, 2000 (c)           $   965       $  5,137       $(1,140)      $  (623)      $ 4,339

Year Ended January 2, 1999               $   259       $  1,309       $  (592)      $   (11)      $   965

Year Ended January 3, 1998               $   896       $    299       $  (832)      $  (104)      $   259

(a) Includes allowance of businesses acquired during the year as described in
    Note 3 to Consolidated Financial Statements in the Registrant's 1999 Annual
    Report to Shareholders and the effect of foreign currency translation.
(b) The nature of the activity in this account is described in Note 3 to
    Consolidated Financial Statements in the Registrant's 1999 Annual Report to
    Shareholders.
(c) Includes reserves established related to an acquisition completed in 1998.
(d) Represents reversal of accrued acquisition expenses and corresponding
    reduction of cost in excess of net assets of acquired companies resulting
    from finalization of restructuring plans and the effect of foreign currency
    translation.


                                       15

                                  EXHIBIT INDEX
Exhibit
Number         Description of Exhibit

 2.1           Asset and Stock Purchase Agreement dated as of January 28, 1994,
               between Thermo Electron and Baker Hughes Incorporated (filed as
               Exhibit 2.1 to the Registrant's Current Report on Form 8-K
               relating to events occurring on March 16, 1994 [File No. 1-9567]
               and incorporated herein by reference).

 2.2           Assignment and Assumption Agreement dated March 16, 1994, among
               Thermo Electron, the Registrant, and Thermo Instrument Systems
               Inc. (filed as Exhibit 2.2 to the Registrant's Current Report on
               Form 8-K relating to events occurring on March 16, 1994 [File No.
               1-9567] and incorporated herein by reference).

 2.3           Agreement and Plan of Merger dated as of November 29, 1995, by
               and among the Registrant, ATI Merger Corp., Analytical
               Technology, Inc., and, for certain limited purposes, Thermo
               Instrument Systems Inc. (filed as Exhibit 2 to the Registrant's
               Current Report on Form 8-K relating to events occurring on
               November 29, 1995 [File No. 1-9567] and incorporated herein by
               reference).

 2.4           Asset and Share Purchase Agreement dated as of November 29, 1995,
               by and among Thermo Instrument Systems Inc., ATI Acquisition
               Corp., Analytical Technology, Inc., and, for certain limited
               purposes, the Registrant (filed as Exhibit 10(a) to the
               Registrant's Current Report on Form 8-K relating to events
               occurring on November 29, 1995 [File No.
               1-9567] and incorporated herein by reference).

 2.5           Asset Purchase Agreement dated as of January 25, 1996, among
               Thermedics Detection Limited, Moisture Systems Corporation,
               Moisture Systems Limited, and Anacon Corporation (filed as
               Exhibit 2.5 to the Registrant's Annual Report on Form 10-K for
               the fiscal year ended December 30, 1995 [File No. 1-9567] and
               incorporated herein by reference). Schedules to this Agreement
               have been omitted pursuant to Rule 601(b)(2) of Regulation S-K.
               The Registrant hereby undertakes to furnish supplementally a copy
               of any omitted schedule to the Commission upon request.

 2.6           Agreement and Plan of Reorganization among Thermo Cardiosystems Inc., ITC Acquisition
               Corp., Thermo Electron Corporation, ITC Holdings Inc., and International Technidyne
               Corporation dated as of May 2, 1997 (filed as Exhibit 2.1 to Thermo Cardiosystems'
               Quarterly Report on Form 10-Q for the quarter ended March 29, 1997 [File No. 1-10114] and
               incorporated herein by reference).

 3.1           Articles of Organization (filed as Exhibit 3(a) to the
               Registrant's Annual Report on Form 10-K for the fiscal year ended
               December 31, 1988 [File No. 1-9567] and incorporated herein by
               reference).

 3.2           Amendment to Articles of Organization dated October 25, 1993 (filed as
               Exhibit 3(c) to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended October 2, 1993 [File No. 1-9567]
               and incorporated herein by reference).

 3.3           Articles of Amendment to Articles of Organization of the Registrant (filed
               as Exhibit 3(i) to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended June 29, 1996 [File No. 1-9567] and
               incorporated herein by reference).

 3.4           Amended and Restated By-laws of the Registrant (filed as Exhibit
               10.14 to the Registrant's Quarterly Report on Form 10-Q for the
               fiscal quarter ended July 3, 1999 [File No. 1-9567] and
               incorporated herein by reference).


                                       16

Exhibit
Number         Description of Exhibit

 4.1           Fiscal Agency Agreement dated January 5, 1994, among Thermo Cardiosystems, Thermo
               Electron, and Chemical Bank (filed as Exhibit 4.11 to Thermo Cardiosystems' Annual Report
               on Form 10-K for the fiscal year ended January 1, 1994 [File No. 1-10114] and
               incorporated herein by reference).

 4.2           Reserved.

 4.3           Fiscal Agency Agreement dated as of June 3, 1996, among
               Thermedics, Thermo Electron, and Chemical Bank, as fiscal agent
               (filed as Exhibit 4 to the Registrant's Quarterly Report on Form
               10-Q for the fiscal quarter ended June 29, 1996 [File No. 1-9567]
               and incorporated herein by reference).

 4.4           Guarantee Reimbursement Agreement dated February 7, 1994, among
               Thermo Cardiosystems, Thermo Voltek, the Registrant, and Thermo
               Electron (filed as Exhibit 4.4 to the Registrant's Annual Report
               on Form 10-K for the fiscal year ended January 1, 1994 [File No.
               1-9567] and incorporated herein by reference).

 4.5           Fiscal Agency Agreement dated as of May 14, 1997, among Thermo
               Cardiosystems Inc., Thermo Electron Corporation, and Bankers
               Trust Company as fiscal agent relating to $70 million principal
               amount of 4 3/4% Convertible Subordinated Debentures due 2004
               (filed as Exhibit 4 to Thermo Cardiosystems' Quarterly Report on
               Form 10-Q for the quarter ended June 28, 1997 [File No. 1-10114]
               and incorporated herein by reference).

               The Registrant hereby agrees, pursuant to Item 601(b)(4)(iii)(A)
               of Regulation S-K, to furnish to the Commission upon request, a
               copy of each other instrument with respect to other long-term
               debt of the Company or its subsidiaries.

10.1           Amended and Restated Corporate Services Agreement between Thermo
               Electron and the Registrant dated as of January 3, 1993 (filed as
               Exhibit 10(a) to the Registrant's Annual Report on Form 10-K for
               the fiscal year ended January 2, 1993 [File No. 1-9567] and
               incorporated herein by reference).

10.2           Lease dated November 1983 between WGO Limited Partnership, as Lessor
               and the Registrant, as Lessee (filed as Exhibit 10(l) to the
               Registrant's Registration Statement on Form S-1 [Reg. No.
               2-96962] and incorporated herein by reference; amendments thereto
               filed as Exhibit 10(l) to the Registrant's Annual Report on Form
               10-K for the fiscal year ended December 31, 1988 [File No.
               1-9567] and incorporated herein by reference).

10.3           Thermo Electron Corporate Charter as amended and restated
               effective January 3, 1993 (filed as Exhibit 10(h) to the
               Registrant's Annual Report on Form 10-K for the fiscal year ended
               January 2, 1993 [File No. 1-9567] and incorporated herein by
               reference).

10.4           Lease dated August 25, 1978, between National Boulevard Bank of Chicago and Walpak
               Company (filed as Exhibit 10(p) to the Registrant's Annual Report on Form 10-K for the
               fiscal year ended December 31, 1988 [File No. 1-9567] and incorporated herein by
               reference).

10.5           Exclusive Base Technology License Agreement between Thermo
               Electron and the Registrant dated January 8, 1988 (filed as
               Exhibit 10(q) to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended April 2, 1988 [File No. 1-9567] and
               incorporated herein by reference).


                                       17

Exhibit
Number         Description of Exhibit

10.6           Research and Development Contract between Thermo Electron and the Registrant dated
               January 8, 1988 (filed as Exhibit 10(r) to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended April 2, 1988 [File No. 1-9567] and incorporated herein by
               reference).

10.7           Exclusive License and Marketing Agreement between Thermo Electron
               and the Registrant dated January 8, 1988 (filed as Exhibit 10(s)
               to the Registrant's Quarterly Report on Form 10-Q for the fiscal
               quarter ended April 2, 1988 [File No. 1-9567] and incorporated
               herein by reference).

10.8           Intellectual Property Cross-license Agreement between the Registrant
               and Thermo Cardiosystems (filed as Exhibit 10(i) to Thermo
               Cardiosystems' Registration Statement on Form S-1 [Reg. No.
               33-25144] and incorporated herein by reference).

10.9           Amendment No. 1 dated March 29, 1991, to Exclusive License and
               Marketing Agreement between the Registrant and Thermo Electron
               (filed as Exhibit 10(r) to the Registrant's Quarterly Report on
               Form 10-Q for the fiscal quarter ended March 30, 1991 [File No.
               1-9567] and incorporated herein by reference).

10.10          Management Agreement by and between Thermo Electron and the Registrant dated November 15,
               1991 (filed as Exhibit 10(t) to the Registrant's Annual Report on Form 10-K for the
               fiscal year ended December 28, 1991 [File No. 1-9567] and incorporated herein by
               reference).

10.11          Agreement dated May 26, 1993, between Thermo Cardiosystems and The Polymer Technology
               Group, Incorporated (filed as Exhibit 10(nn) to the Registrant's Quarterly Report on Form
               10-Q for the fiscal quarter ended July 3, 1993 [File No. 1-9567] and incorporated herein
               by reference).

10.12          Reserved.

10.13          $38,000,000 Promissory Note dated as of December 11, 1995, issued
               by the Registrant to Thermo Electron (filed as Exhibit 10(b) to
               the Registrant's Current Report on Form 8-K relating to events
               occurring on November 29, 1995 [File No. 1-9567] and incorporated
               herein by reference).

10.14          $15,000,000 Promissory Note dated as of February 13, 1996, issued by the Company to
               Thermo Electron (filed as Exhibit 10 to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended March 30, 1996 [File No. 1-9567] and incorporated herein by
               reference).

10.15-17       Reserved.

10.18          Incentive Stock Option Plan of the Registrant (filed as Exhibit 10(d) to
               the Registrant's Registration Statement on Form S-1 [Reg. No.
               33-84380] and incorporated herein by reference). (Maximum number
               of shares issuable in the aggregate under this plan and the
               Registrant's Nonqualified Stock Option Plan is 1,931,923 shares,
               after adjustment to reflect share increases approved in 1986 and
               1992, 5-for-4 stock split effected in January 1985, 4-for-3 stock
               split effected in September 1985, and 3-for-2 stock splits
               effected in October 1986 and November 1993.)


                                       18

Exhibit
Number         Description of Exhibit

10.19          Amended and Restated Nonqualified Stock Option Plan of the
               Registrant (filed as Exhibit 10.6 to the Registrant's Quarterly
               Report on Form 10-Q for the fiscal quarter ended July 3, 1999
               [File No. 1-9567] and incorporated herein by reference). (Maximum
               number of shares issuable in the aggregate under this plan and
               the Registrant's Incentive Stock Option Plan is 1,931,923 shares,
               after adjustment to reflect share increases approved in 1986 and
               1992, 5-for-4 stock split effected in January 1985, 4-for-3 stock
               split effected in September 1985, and 3-for-2 stock splits
               effected in October 1986 and November 1993.)

10.20          Amended and Restated Equity Incentive Plan of the Registrant
               (filed as Exhibit 10.7 to the Registrant's Quarterly Report on
               Form 10-Q for the fiscal quarter ended July 3, 1999 [File No.
               1-9567] and incorporated herein by reference). (Maximum number of
               shares issuable is 1,500,000 shares, after adjustment to reflect
               3-for-2 stock split effected in November 1993.)

               In addition to the stock-based compensation plans of the
               Registrant, the executive officers of the Registrant may be
               granted awards under stock-based compensation plans of Thermo
               Electron for services rendered to the Registrant or to such
               affiliated corporations. The terms of such plans are
               substantially the same as those of the Registrant's Equity
               Incentive

10.21          Amended and Restated Directors Stock Option Plan of the
               Registrant (filed as Exhibit 10.8 to the Registrant's Quarterly
               Report on Form 10-Q for the fiscal quarter ended July 3, 1999
               [File No. 1-9567] and incorporated herein by reference).

10.22          Amended and Restated Deferred Compensation Plan for Directors of the Registrant (filed as
               Exhibit 10.9 to the Registrant's Quarterly Report on Form 10-Q for the fiscal quarter
               ended July 3, 1999 [File No. 1-9567] and incorporated herein by reference).

10.23          Amended and Restated Thermedics Inc. - Thermo Cardiosystems Inc. Nonqualified Stock
               Option Plan (filed as Exhibit 10.10  to the Registrant's Quarterly Report on Form 10-Q
               for the fiscal quarter ended July 3, 1999 [File No. 1-9567] and incorporated herein by
               reference).

10.24          Amended and Restated Thermedics Inc. - Thermedics Detection Inc. Nonqualified Stock
               Option Plan (filed as Exhibit 10.11 to the Registrant's Quarterly Report on Form 10-Q for
               the fiscal quarter ended July 3, 1999 [File No. 1-9567] and incorporated herein by
               reference).

10.25          Amended and Restated Thermedics Inc. - Thermo Sentron Inc. Nonqualified Stock Option Plan
               (filed as Exhibit 10.12 to the Registrant's Quarterly Report on Form 10-Q for the fiscal
               quarter ended July 3, 1999 [File No. 1-9567] and incorporated herein by reference).

10.26          Amended and Restated Thermedics Inc. - Thermo Voltek Corp. Nonqualified Stock Option Plan
               (filed as Exhibit 10.13 to the Registrant's Quarterly Report on Form 10-Q for the fiscal
               quarter ended July 3, 1999 [File No. 1-9567] and incorporated herein by reference).

10.27          Restated Stock Holdings Assistance Plan and Form of Promissory Note (filed as Exhibit
               10.27 to the Registrant's Annual Report on Form 10-K for the fiscal year ended January 3,
               1998 [File No. 1-9567] and incorporated herein by reference).


                                       19

Exhibit
Number         Description of Exhibit

10.28          Reserved.

10.29          Master Cash Management, Guarantee Reimbursement, and Loan
               Agreement dated as of June 1, 1999, between the Registrant and
               Thermo Electron Corporation (filed as Exhibit 10.1 to the
               Registrant's Quarterly Report on Form 10-Q for the fiscal quarter
               ended July 3, 1999 [File No. 1-9567] and incorporated herein by
               reference).

10.30          Master Cash Management, Guarantee Reimbursement, and Loan
               Agreement dated as of June 1, 1999, between Thermo Cardiosystems
               Inc. and Thermo Electron Corporation (filed as Exhibit 10.1 to
               Thermo Cardiosystems Inc.'s Quarterly Report on Form 10-Q for the
               quarter ended July 3, 1999 [File No. 1-10114] and incorporated
               herein by reference).

10.31          Master Cash Management, Guarantee Reimbursement, and Loan
               Agreement dated as of June 1, 1999, between Thermedics Detection
               Inc. and Thermo Electron Corporation (filed as Exhibit 10.1 to
               Thermedics Detection Inc.'s Quarterly Report on Form 10-Q for the
               quarter ended July 3, 1999 [File No. 1-12745] and incorporated
               herein by reference).

10.32          Master Cash Management, Guarantee Reimbursement, and Loan
               Agreement dated as of June 1, 1999, between Thermo Sentron Inc.
               and Thermo Electron Corporation (filed as Exhibit 10.1 to Thermo
               Sentron Inc.'s Quarterly Report on Form 10-Q for the quarter
               ended July 3, 1999 [File No. 1-14254] and incorporated herein by
               reference).

10.33          Amended and Restated $13,000,000 Promissory Note dated as of June 30, 1999, issued by
               Thermo Sentron Inc. to Thermo Electron Corporation (filed as Exhibit 10.2 to Thermo
               Sentron Inc.'s Quarterly Report on Form 10-Q for the quarter ended July 3, 1999 [File No.
               1-14254] and incorporated herein by reference).

  13           Annual Report to Shareholders for the year ended January 1, 2000
               (only those portions incorporated herein by reference).

  21           Subsidiaries of the Registrant.

  23           Consent of Arthur Andersen LLP.

27.1           Financial Data Schedule for the year ended January 1, 2000
               (restated for discontinued operations).

27.2           Financial Data Schedule for the year ended January 2, 1999
               (restated for discontinued operations).

27.3           Financial Data Schedule for the year ended January 3, 1998
               (restated for discontinued operations).