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                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                    FORM 10-Q
         --------------------------------------------------------------


[X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                For the quarterly period ended December 31, 1999
                                       OR

[ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OR THE SECURITIES EXCHANGE ACT OF 1934
                        For the transition period from______ to_______


                          Commission file number 1-9114

                             MYLAN LABORATORIES INC.
             (Exact Name of registrant as specified in its charter)

                  Pennsylvania                          25-1211621
         (State or other jurisdiction of           (I.R.S. Employer
          incorporation or organization)            Identification No.)

               130 Seventh Street
             1030 Century Building
            Pittsburgh, Pennsylvania                       15222
   (Address of principal executive offices)              (Zip Code)

                                  412-232-0100
              (Registrant's telephone number, including area code)

                                 Not Applicable
         (Former name, former address and former fiscal year, if changed
          since last report)

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  twelve months (or for such shorter period that the Registrant was
required  to file  such  reports),  and  (2) has  been  subject  to such  filing
requirements for the past 90 days:

                           YES   X                            NO
                               -----

Indicate the number of shares  outstanding  of each of the  issuer's  classes of
common stock, as of the latest practicable date

                                                        Outstanding at
 Class of Common Stock                                 February 8, 2000
 ---------------------                                 ----------------
    $.50 par value                                        129,334,180








                    MYLAN LABORATORIES INC. AND SUBSIDIARIES


                                      INDEX



                                                                       Page
                                                                       Number
                                                                     ---------

PART I. FINANCIAL INFORMATION

        ITEM 1: Financial Statements

           Consolidated Statements of Earnings - Three and
             Nine Months Ended December 31, 1999 and 1998                 2

           Consolidated Balance Sheets - December 31, 1999
             and March 31, 1999                                           3

           Consolidated Statements of Cash Flows - Nine
             Months Ended December 31, 1999 and 1998                      4

           Notes to Consolidated Financial Statements -
             Nine Months Ended December 31, 1999                        5 - 8

        ITEM 2:       Management's Discussion and Analysis of
                      Financial Condition and Results of
                      Operations                                        9 - 13

        ITEM 3: Quantitative and Qualitative Disclosures
                      About Market Risk                                  13

PART II. OTHER INFORMATION

        ITEM 1: Legal Proceedings                                      13 - 15

        ITEM 6: Exhibits and Reports on Form 8-K                         16


SIGNATURES                                                               16










                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                       CONSOLIDATED STATEMENTS OF EARNINGS
                     (In thousands except per share amounts)

                                    UNAUDITED


                                                 Three Months Ended            Nine Months Ended
                                                 -------------------            -----------------
                                                    December 31,                  December 31,
                                                   -------------                  ------------
                                                 1999           1998          1999        1998
                                               ---------     ----------      -------     ------
                                                                          

NET SALES                                      $203,877       $186,195       $575,461   $530,505


COST AND EXPENSES:
        Cost of Sales                            92,725         86,479        257,250    253,591
        Research and Development                 12,387         12,274         35,651     39,740
        Acquired In-Process
           Research and Development                   -         29,000              -     29,000
        Selling and Administrative               40,417         35,987        117,411     89,431
                                               --------    -----------       ---------  ---------
                                                145,529        163,740        410,312    411,762
EQUITY IN (LOSS) EARNINGS OF SOMERSET            (1,548)         1,113         (2,619)     5,605

OTHER INCOME                                      6,878          4,275          9,640     12,387
                                                --------    -------- --       --------   --------

EARNINGS BEFORE INCOME TAXES                     63,678         27,843        172,170    136,735
INCOME TAXES                                     23,244         19,689         62,717     57,184
                                                --------    -----------       --------   --------
NET EARNINGS                                   $ 40,434    $     8,154       $109,453   $ 79,551
                                                ========    ===========       ========   ========
EARNINGS PER COMMON SHARE:
  Basic                                        $    .31    $       .06       $    .85   $    .64
                                                ========    ===========       ========   ========
  Diluted                                      $    .31    $       .06       $    .84   $    .63
                                                ========    ===========       ========   ========
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
  Basic                                         129,232        128,644        129,183    124,449
                                                ========    ===========       ========   ========
  Diluted                                       130,026        130,339        130,160    126,075
                                                ========    ===========       ========   ========


The Company has paid regular  quarterly cash dividends of $.04 per share since October 1995.


                 See Notes to Consolidated Financial Statements




                                       -2-













                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                           CONSOLIDATED BALANCE SHEETS
                     (In thousands except share information)

                                    UNAUDITED

                                     ASSETS

                                                         December 31,  March 31,
                                                              1999       1999
                                                              
                                                              ----       ----
Current Assets:
    Cash and cash equivalents                             $  237,528 $  189,849
    Marketable securities                                     95,559     69,872
    Accounts receivable - net                                162,687    148,896
    Inventories:
        Raw materials                                         66,977     57,414
        Work in process                                       25,591     20,813
        Finished goods                                        47,651     58,266
                                                          ---------- ----------
                                                             140,219    136,493
    Deferred income tax benefit                               32,032     18,199
    Other current assets                                      15,837     19,650
                                                          ---------- ----------
           Total Current Assets                              683,862    582,959


Property, Plant and Equipment - at cost                      266,148    244,793
    Less accumulated depreciation                            102,295     90,157
                                                          ---------- ----------
                                                             163,853    154,636
Investment in and Advances to Somerset                        31,160     34,114
Intangible Assets - net of accumulated amortization          325,225    336,003
Other Assets                                                 104,942     98,949
                                                          ---------- ----------
Total Assets                                              $1,309,042 $1,206,661
                                                          ========== ==========
                 LIABILITIES AND SHAREHOLDERS' EQUITY

Current Liabilities:
    Trade accounts payable                                $   16,869 $   12,142
    Current portion of long-term obligations                  16,336     16,941
   Income taxes payable                                       11,458        821
    Cash dividends payable                                     5,188      5,178
    Other current liabilities                                 52,476     61,279
                                                          ---------- ----------
           Total Current Liabilities                         102,327     96,361
Long-Term Obligations                                         23,684     26,827
Deferred Income Tax Liability                                 25,161     23,568
Shareholders' Equity:
    Preferred stock, par value $.50 per share, authorized
      5,000,000 shares, issued and outstanding - none           -          -
    Common stock, par value $.50 per share, authorized
      300,000,000 shares, issued 130,132,593 shares at
      December 31, 1999 and 129,968,514 shares at
      March 31, 1999                                          65,066     64,984
    Additional paid-in capital                               314,714    311,995
    Retained earnings                                        783,952    690,003
    Accumulated other comprehensive income                     2,320      1,105
                                                          ----------
                                                           1,166,052  1,068,087
    Less treasury stock - at cost, 888,578 shares at
     December 31, 1999 and March 31, 1999                      8,182      8,182
                                                          ---------- ----------
      Total Shareholders' Equity                           1,157,870  1,059,905
                                                          ---------- ----------
Total Liabilities and Shareholders' Equity                $1,309,042 $1,206,661
                                                          ========== ==========

                 See Notes to Consolidated Financial Statements


                                       -3-







                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                      CONSOLIDATED STATEMENTS OF CASH FLOWS
              FOR THE NINE MONTHS ENDED DECEMBER 31, 1999 AND 1998
                                 (In thousands)

                                    UNAUDITED


                                                            1999           1998
                                                            ----           ----
                                                               

CASH FLOWS FROM OPERATING ACTIVITIES
    Net earnings                                        $109,453       $ 79,551
    Adjustments to reconcile net earnings to net
        cash provided from operating activities:
           Depreciation and amortization                  27,112         18,995
           Deferred income tax benefit                   (13,303)       (10,531)
           Equity in the loss(earnings)of Somerset         2,619         (5,606)
           Cash received from Somerset                       335          3,135
           Allowances on accounts receivable              32,160         13,954
           Acquired in-process research and development        -         29,000
           Other noncash expense                           7,225            154
        Changes in operating assets and liabilities:
           Accounts receivable                           (45,901)       (27,029)
           Inventories                                    (3,669)         1,049
           Trade accounts payable                          4,727         (4,338)
           Income taxes payable                           11,853          9,561
           Other operating assets and liabilities         (8,679)           256
                                                         --------        --------
Net cash provided from operating activities              123,932        108,151
CASH FLOWS FROM INVESTING ACTIVITIES
    Additions to property, plant and equipment           (21,355)       (11,267)
    Increase in intangible and other assets              (11,963)        (3,397)
    Proceeds from investment securities                  112,630         22,801
    Purchase of investment securities                   (135,967)       (20,611)
    Cost of acquisition net of cash acquired                -             1,467
                                                        --------       --------
Net cash used in investing activities                    (56,655)       (11,007)
CASH FLOWS FROM FINANCING ACTIVITIES
    Payments on long-term obligations                     (6,186)        (6,673)
    Cash dividends paid                                  (15,494)       (14,679)
  Proceeds from exercise of stock options                  2,082          8,566
                                                        --------       --------
Net cash used in financing activities                    (19,598)       (12,786)
                                                       --------       --------

Net increase in cash and cash equivalents                 47,679         84,358
Cash and cash equivalents - beginning of period          189,849        103,756
                                                        --------       --------
Cash and cash equivalents - end of period               $237,528       $188,114
                                                        ========       ========
CASH PAID DURING THE PERIOD FOR:
    Interest                                            $    646       $    279
                                                        ========       ========
    Income Taxes                                        $ 64,167       $ 58,157
                                                        ========       ========


                 See Notes to Consolidated Financial Statements











                                       -4-






                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                NINE MONTHS ENDED
                                DECEMBER 31, 1999

                                    Unaudited

A.    In  the  opinion  of  management,  the  accompanying  unaudited  financial
      statements  contain all adjustments  (consisting of only normal  recurring
      accruals)  necessary  to present  fairly the  financial  position of Mylan
      Laboratories  Inc. and  subsidiaries  (the  "Company")  as of December 31,
      1999, and March 31, 1999, together with the results of operations and cash
      flows for the  interim  periods  ended  December  31,  1999 and 1998.  The
      consolidated  results of  operations  for the three and nine months  ended
      December 31, 1999,  are not  necessarily  indicative  of the results to be
      expected for the full year.

B.    These interim financial  statements should be read in conjunction with the
      consolidated  financial statements and notes thereto in the Company's 1999
      Annual Report and Report on Form 10-K.

C.    Diluted  earnings  per common  share is computed by dividing  net earnings
      available to common  shareholders  by the weighted  average  common shares
      outstanding  adjusted for the dilutive effect of options granted under the
      Company's stock option plans.  The effect of dilutive stock options on the
      weighted  average common shares  outstanding was 794,000 and 1,695,000 for
      the three  months  ended  December  31,  1999 and 1998,  and  977,000  and
      1,626,000 for the nine months ended December 31, 1999 and 1998.

D.    Total  comprehensive  income for the three and nine months ended  December
      31, 1999 and 1998, is as follows: (in thousands)


                                       Three Months Ended   Nine Months Ended
                                          December 31,         December 31,
                                          ------------         ------------
                                           1999    1998         1999     1998
                                           ----    ----         ----     ----
Net earnings                             $40,434  $8,154     $109,453  $79,551

Other comprehensive income, net of tax:

  Unrealized (loss) gain on marketable
      securities                             (27)    (14)       3,419   (2,015)
  Adjustment for loss(gains) included
    in net earnings                          331    (169)      (2,204)    (208)
                                          -------  ------      -------   ------
Comprehensive income                     $40,738  $7,971     $110,668  $77,328
                                         ======== =======    ========= ========


      Accumulated other comprehensive income, as reflected on the balance sheet,
is comprised  solely of the  unrealized  gain on marketable  securities,  net of
deferred income taxes.


                                       -5-






                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                NINE MONTHS ENDED
                                DECEMBER 31, 1999

                                    Unaudited

E.   The following  table  presents the  comparative  operating  results for the
     Company's operating segments: (in thousands)

                              Three Months Ended       Nine Months Ended
                                  December 31,            December 31,
                                  ------------            ------------


                                1999       1998         1999       1998
                                ----       ----         ----       ----
  Generic Segment:
    Net Sales                 $168,223   $158,159     $483,974   $472,492
    Segment Profit              65,495     58,254      193,247    166,413


  Branded Segment:
    Net Sales                 $ 35,654    $ 28,036      $91,487  $ 58,013
    Segment Profit               5,942       6,410       13,126    12,417
                              $ (7,759)
  Corporate                   $ (7,759)   $(36,821)    $(34,203) $(42,095)

  Consolidated:
    Net Sales                 $203,877    $186,195     $575,461  $530,505

    Pretax Earnings             63,678      27,843      172,170   136,735


      Segment net sales  represents  sales to unrelated  third parties.  Segment
      profit   represents   segment  gross  profit  less  direct   research  and
      development,  sales and marketing and administrative  expenses.  Corporate
      includes   legal   costs,   goodwill    amortization,    other   corporate
      administrative expenses and nonoperating income and expense. For the three
      and nine months ended  December 31,  1998,  Corporate  includes a one-time
      charge of $29,000,000  for acquired  in-process  research and  development
      relating to the Penederm acquisition.

F.    A  subsidiary  of the  Company  was  involved  in a  dispute  with  KaiGai
      Pharmaceuticals,  Co.,  Ltd.  ("KaiGai")  relating to a license and supply
      contract for  nitroglycerin  transdermal  patches which both parties claim
      was breached by the other. KaiGai sought damages in excess of $20,000,000.
      The dispute was subject to binding  arbitration  and in November 1999, the
      arbitration panel denied KaiGai's request for damages.

      In November 1999, the Company and a state agency entered into a settlement
      concerning certain contract pricing matters.  The settlement was satisfied
      without  a  significant  effect on the  Company's  financial  position  or
      results of operations.



                                       -6-







                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                NINE MONTHS ENDED
                                DECEMBER 31, 1999

                                    Unaudited

F.    (cont.) The Company had an agreement with Genpharm Inc. ("Genpharm") where
      it benefitted from the sale of ranitidine HCl tablets by Novopharm Limited
      ("Novopharm")  under a separate  agreement between Genpharm and Novopharm.
      Based on an  independent  audit,  Genpharm  initiated  a  lawsuit  against
      Novopharm to resolve contract interpretation issues and collect additional
      funds due. In response to Genpharm's suit,  Novopharm filed  counterclaims
      against  both  Genpharm  and  the  Company   claiming  damages  of  up  to
      $60,000,000.  The Company believes the counterclaims  against Genpharm and
      the Company are without merit and will vigorously defend its position.

      In June 1998,  the Company  filed suit in the Los Angeles  Superior  Court
      against  American  Bioscience,   Inc.  ("ABI"),   American  Pharmaceutical
      Partners,  Inc.  ("APP") and certain of their directors and officers.  The
      Company's suit seeks various legal and equitable remedies. The Los Angeles
      Superior Court issued a preliminary  injunction  order which,  among other
      things,  prohibits the defendants from transferring or disposing of funds,
      assets,   technology  or  property   without  the  Company's   consent  or
      commingling  assets,  property,  technology  or  personnel  with  those of
      another  company.  In June  1999,  the  defendants  filed an answer to and
      cross-complaint   against  the  Company.   The  cross-  complaint  alleges
      violations  of  California  state  laws,   interference  with  contractual
      relations and prospective economic advantage,  fraud,  slander,  libel and
      other allegations.  The cross-complainants  seek unspecified  compensatory
      and  punitive  damages.  The Company  believes  the  cross-complaints  are
      without merit and intends to vigorously defend its position.

      On December 22, 1998, the Federal Trade  Commission  ("FTC") filed suit in
      U.S. District Court for the District of Columbia (the "Court") against the
      Company.  The FTC's complaint  alleges the Company engaged in restraint of
      trade,   monopolization,   attempted   monopolization  and  conspiracy  to
      monopolize,  arising out of certain agreements involving the supply of raw
      materials  used to  manufacture  two drugs.  The FTC also sued in the same
      case the foreign  supplier of the raw  materials,  the  supplier's  parent
      company  and  its  United  States  distributor.  Under  the  terms  of the
      agreements  related  to these raw  materials,  the  Company  has agreed to
      indemnify these parties.

      The Company is a party to other suits involving the Attorneys General from
      33 states and more than 25  putative  class  actions  that allege the same
      conduct  alleged  in the FTC suit as well as alleged  violations  of state
      consumer protection laws.

                                       -7-







                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                NINE MONTHS ENDED
                                DECEMBER 31, 1999
                                    Unaudited

F.    (cont.) A qui tam  action  was  commenced  by a private  party in the U.S.
      District Court for the District of South Carolina purportedly on behalf of
      the United  States  alleging  violations of the False Claims Act and other
      statutes.

      The relief  sought by the FTC includes an  injunction  barring the Company
      from engaging in the challenged  conduct,  recision of certain  agreements
      and disgorgement in excess of $120,000,000. The states and private parties
      seek similar  relief,  treble damages and  attorneys'  fees. The Company's
      motions to dismiss several of the private actions were granted.

      A class action suit was filed  alleging  violations of federal  securities
      laws by the Company and certain  directors  and  officers of the  Company.
      Without specifying a dollar amount, the suit sought compensatory  damages.
      The Company's motion to dismiss the federal securities case was granted on
      December 22, 1999. A notice of appeal has been filed.

      The Company had filed motions to dismiss the FTC complaint and significant
      portions of the State Attorneys General complaint. In July 1999, the Court
      denied the  Company's  motion to dismiss  the FTC  complaint.  The Company
      filed a motion  requesting the Court to certify its ruling with respect to
      the jurisdictional issue for expedited appeal to the U.S. Court of Appeals
      for the District of Columbia. This motion was denied. The Court granted in
      part and denied in part the  Company's  motion to dismiss  portions of the
      State Attorneys General complaint.  In so doing, the Court limited certain
      theories  of recovery  asserted  by the  states.  Some States have filed a
      motion with the Court  requesting  that it reconsider  certain claims that
      were  dismissed,  and,  in December  1999,  the Court  reinstated  certain
      claims.

      In February 2000, the Company received notice of threatened  litigation by
      another generic manufacturer.  The potential complaint is based on similar
      factors  alleged in the FTC  litigation  relating to the  generic  product
      clorazepate.

      The Company  believes  that it has  meritorious  defenses to the claims in
      these matters and intends to vigorously defend them.  Although the Company
      believes it has meritorious  defenses to the claims,  an adverse result in
      these  suits  could  have a  material  adverse  effect  on  the  Company's
      financial position and results of its operations.

                                       -8-






                    MYLAN LABORATORIES INC. AND SUBSIDIARIES
                         PART 1 - FINANCIAL INFORMATION

ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS

Introduction

      Net earnings for the quarter ended  December 31, 1999,  were $40.4 million
or $.31 per share  compared to $8.2 million or $.06 per share for the same prior
year  period.  Net  earnings  for the nine month  period  then ended were $109.5
million or $.84 per share  compared  to $79.6  million or $.63 per share for the
same prior year period.  Prior year earnings were affected by a one-time  charge
of $29  million for  acquired  in-process  research  and  development  ("IPR&D")
relating to the  acquisition  of Penederm  Inc.  ("Penederm")  in October  1998.
Excluding the one-time charge for acquired  IPR&D,  net earnings for the quarter
ended  December  31,  1998,  were  $37.2  million  or $.29 per share and the net
earnings for the nine months ended  December  31, 1998,  were $108.6  million or
$.86 per share.

      All  references  to per  share  amounts  in Item 2 are  based  on  diluted
weighted average common shares outstanding.

     The following  table  presents the  comparative  operating  results for the
Company's operating segments: (dollars in millions)


                           Three Months Ended           Nine Months Ended
                               December 31,                December 31,
                               ------------                ------------


                       1999      1998   % Change      1999      1998   % Change
                       ----      ----   ---------     ----      ----   --------
  Generic Segment:
    Net Sales         $ 168.2   $158.2     6%        $ 484.0  $ 472.5      2%
    Gross Profit         86.0     80.5     7%          254.4    238.7      7%
    Segment Profit       65.5     58.2    13%          193.2    166.4     16%
  Branded Segment:
    Net Sales         $  35.7   $ 28.0    27%        $  91.5  $  58.0     58%
    Gross Profit         25.2     19.2    31%           63.8     38.2     67%
    Segment Profit        5.9      6.4    (8%)          13.1     12.4      6%
  Corporate           $  (7.7)  $(36.8)              $ (34.1) $ (42.1)
  Consolidated:
    Net Sales         $ 203.9   $186.2    10%        $ 575.5  $ 530.5      8%
    Gross Profit        111.2     99.7    12%          318.2    276.9     15%
    Pretax Earnings      63.7     27.8   129%          172.2    136.7     26%

                       MYLAN LABORATORIES INC. AND SUBSIDIARIES

      Segment net sales  represents  sales to unrelated  third parties.  Segment
gross  profit  represents  segment  net sales less the  corporate  wide costs of
manufacturing,  warehousing  and shipping  associated  with such sales.  Segment
profit  represents  segment gross profit less direct  research and  development,
sales and marketing and administrative expenses. Corporate includes legal costs,
goodwill amortization,  other corporate administrative expenses and nonoperating
income and  expense.  For the three and nine months  ended  December  31,  1998,
Corporate  includes a one-time  charge of  $29,000,000  for acquired  in-process
research and development relating to the Penederm acquisition.

Results of Operations

Net Sales and Gross Profit

      Net sales for the three  months  ended  December  31,  1999,  were  $203.9
million  compared to $186.2 million for the same prior year period,  an increase
of 10%.  Net sales for the nine months  ended  December  31,  1999,  were $575.5
million  compared to $530.5 million for the same prior year period,  an increase
of 8%. The increase in net sales for the three month period relates  principally
to  increases  in  dermatology  product  sales,  generic  volume and new generic
products.  The  increase  in  net  sales  for  the  nine  month  period  relates
principally to an additional six months of dermatology  product sales related to
Penederm,  an  increase  in  generic  volume,  new  generic  products  and price
increases on selected generic products.

      Gross  profits  increased  $11.5  million  over the prior year three month
period to $111.2 million and $41.3 million to $318.2 million over the prior year
nine month  period.  Gross  margins  (gross profit as a percentage of net sales)
were 55% for the current year three and nine month  periods  compared to 54% and
52% in the prior year comparable periods.

      Generic  gross  profit  increased  7% for both the current  three and nine
month periods as a result of price increases on selected products,  sales of new
products  approved  after  December 31,  1998,  termination  of certain  royalty
arrangements in January 1999 and increased generic volume. Generic units shipped
(excluding unit dose shipments) were 2.4 billion units and 6.4 billion units for
the  current  three and nine  month  periods,  up 13% and 8% from the prior year
periods.  The  increases  during  these  periods  were  offset by  normal  price
deterioration  and a 10% and 8% decrease in gross  profit for the current  three
and nine month periods related to clorazepate and lorazepam.

      Branded gross profit  increased 31% and 67% for the current three and nine
month  periods  over the same  prior  year  three and nine  month  periods.  The
increase in gross profit for the current  three month period is due  principally
to growth for existing dermatology  products.  The increase for the current nine
month period is due principally to an additional six months

                                      -9-





of sales of Penederm and the  additional  growth  previously  mentioned  for the
three month period.


                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

Research and Development

      The Company is  actively  pursuing  and is  involved in joint  development
projects in an effort to broaden its scope of capabilities in bringing to market
new and innovative products. Such arrangements generally provide for payments by
the  Company  only  upon  the  attainment  of  certain  milestones.  While  such
arrangements help to reduce the Company's financial risk for unsuccessful
projects,  fulfillment  of milestones  may result in  fluctuations  in quarterly
research and development expense.

      Expenditures  for research and  development  were $12.4  million and $35.7
million for the three and nine month periods ended  December 31, 1999,  compared
to $12.3 million and $39.7 million for the comparable periods ended December 31,
1998.  The  decrease  for the current nine month period over the prior year nine
month period is due to the  fulfillment of milestones for product  licensing and
development  agreements  reached in the prior year.  This decrease was partially
offset by an additional six months of research expenditures for branded products
of  Penederm.  Core  internal  research  costs are  expected  to increase as the
Company  progresses into the advance stages of development for certain  projects
in future periods.

Selling and Administrative Expenses

      Selling  and  administrative  expenses  were $40.4  million  for the three
months ended December 31, 1999, compared to $36.0 million for the same period in
the prior year.  Expenses  for the nine months ended  December  31,  1999,  were
$117.4 million compared to $89.4 million for the same period in the prior year.

      Corporate administrative expenses were $13.1 million and $41.2 million for
the current  three and nine month  periods  compared to $13.2  million and $31.8
million for the comparable  prior year periods.  For the nine month period,  the
increase is primarily due to higher  goodwill  amortization  related to Penederm
and legal expenses related to the FTC investigation.

      Branded Segment selling and administrative expenses were $16.6 million and
$43.8  million for the current  three and nine month  periods  compared to $11.4
million and $24.3 million for the comparable prior year periods. The increase in
the three  month  period  over the prior  year  period is  primarily  due to the
expansion of the sales and support staff. The increase for the nine month period
is due to the expansion of the sales and support staff, as previously mentioned,
and the inclusion of an additional six months of expenses of Penederm.


                                      -10-







                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

      Generic Segment selling and administrative  expenses decreased 6% to $10.7
million  and 5% to $32.4  million  for the three and nine  month  periods  ended
December  31, 1999.  The  decrease for both the three and nine month  periods is
primarily  related  to reduced  expenses  related to new  product  launches  and
promotional campaigns in the current year periods.

Equity in Earnings

      The equity in the loss of Somerset in the  current  periods was  primarily
the  result  of lower  sales  due to  generic  competition  on  Eldepryl(R)  and
increased expenditures for research and development.  Somerset  Pharmaceuticals,
Inc. is continuing its research for alternative uses for  Eldepryl(R),  which is
expected to result in continued losses in the near term.

Other Income

      The increase in the current  quarter is primarily due to income related to
an investment  in a limited  partnership.  The Company also  recorded  losses on
certain investments, which were deemed to be permanently impaired, that offset a
portion of the above income. The decrease for the current nine month period over
the comparable prior nine month period is primarily  related to the fluctuations
in income of the previously mentioned limited partnership.

Income Taxes

      The  Company's  effective tax rate was 36.5% for both the three and
nine month periods ended December 31, 1999. The effective tax rate for the prior
year comparable  periods was  significantly  impacted by the one-time charge for
acquired IPR&D.

Liquidity, Capital Resources and Financial Condition

      Working  capital  increased to $581.5  million at December 31, 1999,  from
$486.6  million  at March 31,  1999.  The  ratio of  current  assets to  current
liabilities  increased to 6.7 to 1 at December 31, 1999,  from 6.0 to 1 at March
31,  1999.   The  increase  in  working   capital  was   primarily  due  to  the
Company's  net earnings.  In addition to net earnings,  net cash provided
from operating activities was affected by changes in accounts receivable and its
related allowance. The increase in cash used in investing activities principally
resulted from the Company's increased investment in marketable securities
which primarily are short term in nature.

      The Company  continues  to examine  opportunities  to expand its  business
through  product and company  acquisitions.  The  Company's  capital  resources,
financial condition and results of

                                      -11-





operations  could be materially  impacted if the Company were to complete one or
more of such acquisitions.

                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

      Although the Company believes it has meritorious defenses to the claims in
the FTC and  related  suits,  an  adverse  result in these  suits  could  have a
material adverse effect on the Company's business and financial  condition,  due
to the size of the FTC's  disgorgement  claim and the  threat of treble  damages
sought by the states,  as well as possible  damages in the other related  suits.
The Company  expects to incur  substantial  costs in  defending  itself in these
actions.

Year 2000

      As  described  in the  Company's  annual  report on Form 10-K for the year
ended March 31, 1999,  and its  quarterly  reports on Form 10-Q for the quarters
ended June 30,  1999,  and  September  30,  1999,  the Company had  examined its
critical  information  ("IT") and non-IT operating systems for Year 2000 ("Y2K")
compliance.  Since entering the year 2000, the Company has not  experienced  any
significant  disruptions  to its  business  either  directly or by reason of Y2K
related  problems  affecting the Company's  customers or suppliers.  The Company
will  continue  to monitor  its  critical  IT and non-IT  systems  over the next
several  months,  but does not  anticipate  any  significant  Y2K  impact on its
business.  As  previously  disclosed,  the Company  significantly  upgraded  its
computing systems over the last several years, principally for reasons unrelated
to Y2K issues.  Consequently,  the Company did not incur significant incremental
costs in seeking to become Y2K compliant.

Forward-Looking Statements

      The  statements  set  forth in this  Item 2 under  Results  of  Operations
concerning  the  manner in which the  Company  intends  to  conduct  its  future
operations,  potential trends that may impact future results of operations,  and
its  beliefs  or  expectations  about  future  operations  are   forward-looking
statements. The Company may be unable to realize its plans and objectives due to
various important factors,  including, but not limited to, the factors described
under "Forward  Looking  Statements" in Item 7 of the Company's Annual Report on
Form 10-K for the year ended March 31, 1999.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

      The  information  required by Item 3 has been  disclosed in Item 7A of the
Company's  Annual  Report on Form 10-K for the year ended March 31, 1999.  There
has been no material change in the disclosure regarding market risk.

                           PART II. OTHER INFORMATION
ITEM 1. LEGAL PROCEEDINGS


                                      -12-





      Since the date of the filing of the Company's  report on Form 10-Q for the
period  ended  September  30,  1999,  there  have  been no  material  new  legal
proceedings   involving  the  Company  or  any  material  developments  to  such
proceedings, except as described below. See Note F to the Company's consolidated
financial statements and/or "Legal Proceedings" in the Company's

                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

Annual  Report on Form 10-K for the year ended  March 31,  1999,  and  Quarterly
Reports on Form 10-Q for the quarters  ended June 30, 1999,  and  September  30,
1999, for a discussion of certain other legal proceedings  involving the Company
as to which  there have been no  material  developments  since the filing of the
Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 1999.

      A  subsidiary  of the  Company  was  involved  in a  dispute  with  KaiGai
Pharmaceuticals,  Co., Ltd. ("KaiGai") relating to a license and supply contract
for nitroglycerin  transdermal  patches which both parties claim was breached by
the other.  KaiGai  sought  damages in excess of  $20,000,000.  The  dispute was
subject to binding  arbitration,  and, in November 1999, the  arbitration  panel
denied KaiGai's request for damages.

      In November 1999, the Company and a state agency entered into a settlement
concerning  certain  contract  pricing  matters.  The  settlement  was satisfied
without a significant  effect on the Company's  financial position or results of
operations.

      On December 22, 1998, the Federal Trade  Commission  ("FTC") filed suit in
U.S.  District  Court for the  District of Columbia  (the  "Court")  against the
Company.  The FTC's complaint alleges the Company engaged in restraint of trade,
monopolization,  attempted monopolization and conspiracy to monopolize,  arising
out of  certain  agreements  involving  the  supply  of raw  materials  used  to
manufacture two drugs.  The FTC also sued in the same case the foreign  supplier
of the raw  materials,  the  supplier's  parent  company  and its United  States
distributor.  Under the terms of the agreements  related to these raw materials,
the Company has agreed to indemnify these parties.

      The Company is a party to other suits involving the Attorneys General from
33 states and more than 25 putative  class  actions that allege the same conduct
alleged  in the FTC  suit  as  well as  alleged  violations  of  state  consumer
protection  laws. A qui tam action was  commenced by a private party in the U.S.
District Court for the District of South  Carolina  purportedly on behalf of the
United States alleging violations of the False Claims Act and other statutes.

      The relief  sought by the FTC includes an  injunction  barring the Company
from engaging in the  challenged  conduct,  recision of certain  agreements  and
disgorgement  in excess of  $120,000,000.  The states and private  parties  seek
similar  relief,  treble damages and attorneys'  fees. The Company's  motions to
dismiss several of the private actions were granted.

                                      -13-










                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

      A class action suit was filed  alleging  violations of federal  securities
laws by the Company and certain  directors and officers of the Company.  Without
specifying a dollar amount, the suit sought compensatory  damages. The Company's
motion to dismiss the federal  securities case was granted on December 22, 1999.
A notice of appeal has been filed.

      The Company had filed motions to dismiss the FTC complaint and significant
portions  of the State  Attorneys  General  complaint.  In July 1999,  the Court
denied the Company's  motion to dismiss the FTC  complaint.  The Company filed a
motion  requesting  the  Court  to  certify  its  ruling  with  respect  to  the
jurisdictional issue for expedited appeal to the U.S. Court of

      Appeals for the  District of Columbia.  This motion was denied.  The Court
granted in part and denied in part the Company's  motion to dismiss  portions of
the State Attorneys  General  complaint.  In so doing, the Court limited certain
theories  of recovery  asserted  by the states.  Some States have filed a motion
with the Court requesting that it reconsider certain claims that were dismissed,
and, in December 1999, the Court reinstated certain claims.

      In February 2000, the Company received notice of threatened  litigation by
another  generic  manufacturer.  The  potential  complaint  is based on  similar
factors  alleged  in  the  FTC  litigation   relating  to  the  generic  product
clorazepate.

      The Company  believes  that it has  meritorious  defenses to the claims in
these  matters and  intends to  vigorously  defend  them.  Although  the Company
believes it has meritorious  defenses to the claims,  an adverse result in these
suits could have a material adverse effect on the Company's  financial  position
and results of its operations.

      The  Company is  involved  in various  other  legal  proceedings  that are
considered  normal to its  business.  While it is not  feasible  to predict  the
ultimate outcome of such  proceedings,  it is the opinion of management that the
outcome of these suits will not have a material  adverse effect on the Company's
operations, financial position, or liquidity.









                                      -14-










                    MYLAN LABORATORIES INC. AND SUBSIDIARIES

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

      (a)      Exhibit 27 - Financial Data Schedule
      (b)      Reports  on Form 8-K - There  were no  reports  on Form 8-K filed
               during the three months ended December 31, 1999.

                                   SIGNATURES

      Pursuant to the  requirements of the Securities  Exchange Act of 1934, the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.
                                               Mylan Laboratories Inc.
                                                     (Registrant)

DATE  2/14/00
    __________________            /s/   Milan Puskar
                                  Chairman of the Board, Chief
                                  Executive Officer and President
                                  (Principal executive officer)


DATE  2/14/00
   ___________________            /s/   Donald C. Schilling
                                  Vice President of Finance and
                                  Chief Financial Officer
                                  (Principal financial officer)





                                      -15-