PRESS RELEASE                          LIFE SCIENCES RESEARCH, INC.
                                       (OTCBB: LSRI)
                                       PO Box 2360
                                       Mettlers Road
                                       East Millstone, NJ 08875-2360

                                       For Further Information:
                                       Richard Michaelson
                                       Phone:   US: (732) 649-9961
                                       e-mail: LifeSciencesResearch@LSRinc.net



August 3, 2005

                      LSR ANNOUNCES SECOND QUARTER RESULTS


East  Millstone,  New  Jersey,  August 3, 2005 - Life  Sciences  Research,  Inc.
(OTCBB:  LSRI) announced today that revenues for the quarter ended June 30, 2005
were $44.9 million, operating income was $5.4 million, or 12.0% of revenues, and
EBITDA,  excluding  foreign exchange  remeasurement  losses  associated with the
Company's Bonds, was $7.9 million, or 17.5% of revenues.

Revenues  for the quarter  ended June 30, 2005 were 17.3% above the revenues for
the same  period in the prior  year of $38.3  million.  Excluding  the effect of
exchange rate movements,  the increase was 14.9%.  The Company reported net loss
for the quarter ended June 30, 2005 of $1.7 million, compared with net income of
$1.2  million for the same period in the prior year.  Net loss per common  share
for the  quarter  ended  June 30,  2005 was $0.13  compared  with net income per
common share of $0.10 for the same period in the prior year.  Net loss per fully
diluted  share was $0.11 for the quarter  ended June 30, 2005  compared with net
income per fully diluted share of $0.10 for the same period in the prior year.

The net loss in the quarter ended June 30, 2005  included  Other Expense of $2.7
million reflecting a non-cash foreign exchange  remeasurement loss pertaining to
the Convertible  Capital Bonds of $2.4 million and finance  arrangement  fees of
$0.3  million.  In the same  period in the prior  year,  Other  Expense  of $0.6
million comprised a non-cash foreign exchange  remeasurement  loss pertaining to
the  Convertible  Capital  Bonds.  Taxes in the quarter ended June 30, 2005 also
included  $2.4  million  of  taxes   associated  with  the  sale  and  leaseback
transaction  announced on June 14, 2005. Excluding these Other Expense items and
related tax effect, and the transaction related tax charges,  net income for the
quarter ended June 30, 2005 was $3.0 million,  or $0.21 per fully diluted share,
compared with $1.7 million, or $0.14 per fully diluted share for the same period
in the prior year.

Earnings  before  Interest,  Taxes,  Depreciation  and  Amortization  and  Other
Income/(Expense)  ("EBITDA")  was $7.9  million for the  quarter  ended June 30,
2005, or 17.5% of revenues,  compared  with $6.3 million,  or 16.4% of revenues,
for the same period in the prior year.

During the quarter ended June 30, 2005 the Company  repaid  (pound)22.6  million
($41.1  million)  non-bank  debt  with  the  proceeds  of a sale  and  leaseback
transaction  of the  Company's  facilities  and  cash on hand.  Net  days  sales
outstanding  at June 30, 2005 were 13 (19 at June 30, 2004 and 4 at December 31,
2004) and capital  expenditures  totaled $3.7 million in the quarter  ended June
30, 2005, compared with $2.3 million for the same period in the prior year. As a
result net cash used  totaled  $14.5  million in the quarter  ended June 30 2005
compared with $0.3 million for the same period in the prior year.

Cash on hand at June 30, 2005 was $15.4  million  compared with $33.3 million at
December 31, 2004.  Long-term  debt was $75.9  million at June 30, 2005 compared
with $89.7 million at December 31, 2004,  the  reduction  primarily due to a net
repayment of $10.7 million  associated  with the sale and leaseback  transaction
and to exchange rate movements.

Net new business  signings  totaled $46.2 million for the quarter ended June 30,
2005.  This  represented  an  increase  of 11% over the same period in the prior
year.

Revenues  for the six months  ended June 30,  2005 of $88.2  million  were 16.8%
above revenues for the same period in the prior year of $75.6 million. Excluding
the effect of exchange rate movements,  the increase was 14.3%. Operating Income
for the six months  ended June 30, 2005 was $10.6  million,  or 12.0%,  compared
with $6.3  million,  or 8.4% for the same period in the prior year.  The Company
reported  net  income for the six months  ended June 30,  2005 of $0.9  million,
compared with $2.6 million for the same period in the prior year. Net income per
common  share for the six months  ended June 30,  2005 was $0.07  compared  with
$0.22 for the same period in the prior year.

The net income in the six months ended June 30, 2005  included  Other Expense of
$3.4  million   reflecting  a  non-cash  foreign  exchange   remeasurement  loss
pertaining  to the  Convertible  Capital  Bonds  of  $3.1  million  and  finance
arrangement  fees of $0.3 million.  In the same period in the prior year,  Other
Income of $0.7 million comprised a non-cash foreign exchange  remeasurement gain
pertaining to the Convertible  Capital Bonds.  The net income for the six months
ended June 30, 2005 also included $2.4 million of taxes associated with the sale
and  leaseback  transaction  announced on June 14, 2005.  Excluding  these Other
Expense items and related tax effect,  and the transaction  related tax charges,
net income for the first six months of 2005 was $6.2  million or $0.43 per fully
diluted  share,  compared with $2.0 million or $0.16 per fully diluted share for
the same period in the prior year.

EBITDA in the six  months  ended  June 30,  2005 was $15.4  million  or 17.5% of
revenues, compared with $10.9 million, or 14.5% of revenues, for the same period
in the prior year.

Capital  expenditures in the six months ended June 30, 2005 totaled $6.9 million
compared  with $4.6 million in the same period in the prior year.  Net cash used
in the six  months  ended June 30,  2005 was $17.9  million  compared  with $2.1
million for the same period in the prior year.

Brian Cass,  LSR's President and Managing  Director said, "This has been another
exciting  quarter  for the  Company,  including  not just  record  revenues  and
operating income,  but a strategic  financing that strengthens our balance sheet
and  facilitated  the repayment of our existing bank debt.  Cash balances at the
end of the quarter,  although down on the traditionally  high year-end balances,
reflected   that   refinancing,   and  ended  the  quarter  at  $15.4   million,
approximately $0.3 million above the same period last year."

Mr.  Cass  added,  "The market for our  services  to the  pharmaceutical  sector
continues  to be buoyant and this has driven the growth in orders this  quarter.
Revenues also grew  significantly,  with both the UK and US contributing to this
growth, but the US has been particularly  strong. We have continued to invest in
new  capital  projects,   increasing  capacity  in  our  specialist   toxicology
capabilities. We look forward to this coming on stream at the end of the year."

LSR will hold an investor  conference  call to discuss the quarter's  results on
Thursday  morning,  August 4, 2005 at 9:00 a.m.  Eastern Time.  That call can be
listened to by dialing (212) 547-0201;  pass code 39138. We suggest calling five
minutes prior to the scheduled call.

This announcement  contains non-GAAP  financial  measures,  including EBITDA and
non-GAAP  earnings per share which exclude,  among other items,  gains or losses
associated with the non-cash foreign exchange  remeasurement  loss pertaining to
the Company's  Convertible  Capital Bonds and one time charges. We exclude these
items from the non-GAAP  financial  measures because they are outside our normal
operations. We believe that the inclusion of non-GAAP financial measures in this
announcement  helps  investors  to gain a meaningful  understanding  of our core
operating  results and future  prospects,  and is consistent with how management
measures and forecasts the Company's  performance and debt service capabilities,
especially  when comparing such results to prior periods or forecasts.  Non-GAAP
results also allow  investors to compare the  Company's  operations  against the
financial  results of other  companies  in the industry  who  similarly  provide
non-GAAP results.  The non-GAAP financial measures included in this announcement
are not meant to be  considered  superior  to or a  substitute  for  results  of
operations  prepared in accordance  with GAAP.  Reconciliations  of the non-GAAP
financial  measures used in this  announcement  to the most directly  comparable
GAAP financial measures are set forth in the text of this announcement and other
public   filings,   and  can  also  be  found  on  the   Company's   website  at
www.lsrinc.net.

Life  Sciences  Research,  Inc.  is  a  global  contract  research  organization
providing product development  services to the pharmaceutical,  agrochemical and
biotechnology  industries.  LSR brings  leading  technology  and  capability  to
support its clients in  non-clinical  safety  testing of new  compounds in early
stage development and assessment.  The purpose of this work is to identify risks
to humans, animals or the environment resulting from the use or manufacture of a
wide  range of  chemicals  which  are  essential  components  of LSR's  clients'
products.   The  Company's   services  are  designed  to  meet  the   regulatory
requirements of governments  around the world. LSR operates research  facilities
in the United States (the Princeton  Research Center, New Jersey) and the United
Kingdom (Huntingdon and Eye, England).

This announcement  contains statements that may be forward-looking as defined by
the Private Securities Litigation Reform Act of 1995. These statements are based
largely  on  LSR's  expectations  and are  subject  to a  number  of  risks  and
uncertainties,  certain  of  which  are  beyond  LSR's  control,  as more  fully
described in the Company's  SEC filings,  including its Form 10-K for the fiscal
year ended  December  31,  2004,  as filed with the US  Securities  and Exchange
Commission.


                              - tables to follow -





                           Life Sciences Research Inc.
                             Statement of Operations

                                    Unaudited

                                                      Three months ended June 30          Six months ended
                                                                                              June 30

(Dollars in thousands, except per share data)               2005            2004           2005            2004
                                                                                           
Net revenues                                             $44,941         $38,315        $88,235         $75,551
Cost of revenues                                        (32,459)        (28,111)       (63,541)        (57,546)
                                                      -----------    ------------    -----------     -----------
Gross profit                                              12,482          10,204         24,694          18,005
Selling, general and administrative expenses             (7,074)         (6,201)       (14,086)        (11,686)
                                                      -----------    ------------    -----------     -----------
Operating income                                           5,408           4,003         10,608           6,319
Interest income                                               22              14             45              28
Interest expense                                         (1,934)         (1,593)        (3,717)         (3,169)
Other (expense)/income                                   (2,703)           (625)        (3,435)             730
                                                      -----------    ------------    -----------     -----------
Income before income taxes                                   793           1,799          3,501           3,908
Income tax expense                                       (2,455)           (597)        (2,639)         (1,313)
                                                      -----------    ------------    -----------     -----------
Net (loss)/income                                       $(1,662)          $1,202           $862          $2,595
                                                      -----------    ------------    -----------     -----------

(Loss)/income per common share
- - Basic                                                  $(0.13)           $0.10          $0.07           $0.22
- - Diluted                                                $(0.11)           $0.10          $0.06           $0.21

Weighted average common shares outstanding
- - Basic     (000's)                                       12,521          12,050         12,487          12,045
- - Diluted  (000's)                                        14,543          12,346         14,504          12,554







                           Life Sciences Research Inc.
                                  Balance Sheet


(Dollars in thousands, except per share data)                                 June 30, 2005      December 31,2004
                                                                                Unaudited                Audited
ASSETS
                                                                                                 
Current assets:
Cash and cash equivalents                                                          $15,398              $33,341
Accounts receivable, net of allowance of $310 and $255 in 2005 and 2004,
respectively                                                                        27,099               27,841
Unbilled receivables                                                                12,118               11,516
Inventories                                                                          1,926                2,024
Prepaid expenses and other current assets                                            8,830                2,929
                                                                            -------------------  --------------------
                                                                            -------------------  --------------------
Total current assets                                                               $65,371              $77,651

Property and equipment, net                                                        105,437              109,999
Goodwill                                                                               958                  901
Unamortized capital bonds issue costs                                                  163                  271
Deferred income taxes                                                                8,167               11,253
                                                                            -------------------  --------------------
Total assets                                                                      $180,096             $200,075
                                                                            -------------------  --------------------
LIABILITIES AND STOCKHOLDERS' EQUITY/(DEFICIT)
Current liabilities:
Accounts payable                                                                   $14,429              $13,547
Accrued payroll and other benefits                                                   3,145                4,024
Accrued expenses and other liabilities                                              18,702               19,987
Short-term debt                                                                        395                  719
Fees invoiced in advance                                                            32,771               37,574
                                                                            -------------------  --------------------
                                                                            -------------------  --------------------
Total current liabilities                                                          $69,442              $75,851

Long-term debt                                                                      75,933               89,685
Pension liabilities                                                                 34,198               36,603
                                                                            -------------------  --------------------
Total liabilities                                                                 $179,573             $202,139
                                                                            -------------------  --------------------
Commitments and contingencies
Stockholders' equity/(deficit)
Preferred Stock, $0.01 par value. Authorized: 5,000,000
Issued and outstanding : None                                                            -                    -
Non-Voting Common Stock, $0.01 par value. Authorized: 5,000,000
Issued and outstanding: None                                                             -                    -
Voting Common Stock, $0.01 par value.  Authorized 50,000,000
Issued and outstanding at June 30, 2005:  12,526,051
(December 31, 2004: 12,441,281)                                                       $125                 $125
Paid in capital                                                                     75,807               75,671
Less: Promissory notes for the issuance of common stocks                              (261)                (697)
Accumulated comprehensive loss                                                     (33,571)             (34,724)
Accumulated deficit                                                                (41,577)             (42,439)
                                                                            -------------------  --------------------
                                                                            -------------------  --------------------
Total stockholders' equity/(deficit)                                                   523              $(2,064)
                                                                            -------------------  --------------------
                                                                            -------------------  --------------------
Total liabilities and stockholders' equity/(deficit)                              $180,096             $200,075
                                                                            -------------------  --------------------