EXHIBIT 99.1

CONTACTS:   CESAR GARCIA
            PRESIDENT AND CHIEF EXECUTIVE OFFICER
            818-709-1244 X123 OR
            RON STABINER, THE WALL STREET GROUP, INC.
            212-888-4848

FOR IMMEDIATE RELEASE:


                IRIS POSTS RECORD PERFORMANCE AS 1ST QUARTER 2005
                 OPERATING INCOME DOUBLES ON 49% REVENUE GROWTH

    INCREASES 2005 GUIDANCE TO $0.30-$0.35 AND REVENUE GROWTH OF AT LEAST 35%

CHATSWORTH,  CALIF.,  APRIL 28, 2005 - IRIS INTERNATIONAL,  INC. (NASDAQ:  IRIS)
today  announced  record  revenues of $14.0  million for the first quarter ended
March 31, 2005,  and earnings of $0.08 per basic share ($0.07 per fully  diluted
share). The record performance results primarily from sales for its new iQ(R)200
Automated  Urinalysis  Analyzer and increasing  recurring revenues from sales of
consumables.

                            KEY FINANCIAL INDICATORS


                                                           INCREASE
 (000S OMITTED, EXCEPT PER SHARE)      Q1 05      Q1 04   (DECREASE)    % CHG
- ----------------------------------   --------   --------   --------    --------
CONSOLIDATED REVENUE .............   $ 13,964   $  9,375   $  4,589       49%
DIAGNOSTICS REVENUE ..............   $ 11,638   $  7,401   $  4,237       57%
STATSPIN REVENUE .................   $  2,326   $  1,974   $    352       18%
GROSS PROFIT MARGIN ..............   $  6,894   $  4,704   $  2,190       47%
OPERATING INCOME .................   $  2,026   $    968   $  1,058      109%
NET INCOME .......................   $  1,271   $    529   $    742      140%
EPS - BASIC ......................   $   0.08   $   0.04   $   0.04      100%
EPS - DILUTED ....................   $   0.07   $   0.04   $   0.03       75%
DEBT .............................   $      0   $  5,032   $ (5,032)     100%
SHARES OUTSTANDING - BASIC .......     16,218     12,051      4,167       35%
SHARES OUTSTANDING - DILUTED .....     17,294     13,846      3,448       25%
CASH AND CASH EQUIVALENTS ........   $ 13,428   $  3,216   $ 10,212      318%


OTHER Q1 2005 OPERATIONAL HIGHLIGHTS:

o        INCREASED  EARNINGS TO $0.08 PER BASIC SHARE ($0.07* PER DILUTED SHARE)
         FROM $0.04

o        OPERATING INCOME IMPROVED TO $2,026K FROM $968K

o        VERY  STRONG  INTERNATIONAL  DEMAND FOR THE IQ200 AND IQ200  SPRINT(TM)
         ANALYZERS RESULTING IN RECORD INSTRUMENTS REVENUE - THE ACCELERATION OF
         INSTRUMENT  PLACEMENTS SHOULD RESULT IN SIGNIFICANTLY HIGHER CONSUMABLE
         AND SERVICE REVENUES IN FUTURE PERIODS





o        SALES OF  CONSUMABLES  AND SERVICE OF $5.7 MILLION,  AN INCREASE OF 22%
         COMPARED TO Q1 2004

o        NET  OPERATING  LOSS TAX  CARRY-FORWARD  OF $16 MILLION  AVAILABLE  FOR
         FUTURE PERIODS

o        STRONG BALANCE SHEET WITH NO OUTSTANDING DEBT

- --------------------------------------------------------------------------------
* ASSUMES 40% TAX RATE DESPITE  NOLS THAT  ELIMINATE  PAYMENT OF FEDERAL  INCOME
  TAXES FOR 2004.

"We are very  satisfied  with the high demand for iQ200  analyzers  in the first
quarter,"   stated  Cesar  Garcia,   Chief  Executive   Officer  of  IRIS.  "Our
international instrument shipments significantly exceeded our expectations while
domestic instrument  shipments were slightly ahead of expectation.  After a very
strong  fourth  quarter,  I am pleased to report  that we have  achieved  record
quarterly  revenues of $14.0 million and  operating  income of $2.0 million in a
quarter that has been traditionally slow due to lower instruments sales.

"This  is  our  fifth  consecutive   quarter  with  sequential  revenue  growth,
representing  a 49%  increase  over the  corresponding  period  last  year.  Our
performance is beginning to reflect the anticipated increases in consumables and
service,  with quarterly  revenues in this category exceeding prior year results
by more than $1 million, an increase of 22%. We expect this trend to continue to
accelerate  as more  instruments  are put into  routine  use and  more  domestic
customers  acquire  service  contracts,  after the  expiration of the instrument
warranty.

"I am  also  pleased  to  report  that  our  customers  will  be  presenting  12
peer-reviewed  scientific  posters attesting to the superior clinical utility of
our platform at the EUROMEDLAB Conference & Exhibit in Glasgow, Scotland, in May
2005.  This  international  conference  attracts  more than 2,500  participants,
typically laboratory scientists and technologists from around the world. We have
also  been  informed  that  five  additional  peer-reviewed  scientific  posters
submitted by our customers have been accepted for  presentation  at the American
Association of Clinical Chemistry Conference in Orlando,  Florida, in July 2005.
The high level of interest  demonstrated by the medical community  confirms that
the iQ200 Microscopy  Analyzer has been adopted as the standard of care in urine
microscopy."

Mr. Garcia stated that "IRIS' new product  pipeline  became more robust with the
recent U.S. Food and Drug Administration  (FDA) 510k clearance of the iQ200 body
fluids  application  and the market  launch of the Express 3  centrifuge  by our
StatSpin  small medical  devices  division.  Both products will be  commercially
available  during the second  quarter.  We also continue to make progress in our
feasibility  program  to extend  the iQ200  platform  into  advanced  urinalysis
applications  that could  open new  market  opportunities  in the  diagnosis  of
bacteria and rare cell detection in urine -- an estimated  addressable market of
approximately $300 million."

IRIS International  yesterday announced the signing of a definitive agreement to
acquire  the  assets of the  urine  chemistry  strip  product  line from  Quidel
Corporation.  "We are addressing a significant international market gap with the
acquisition of this product line and related intellectual  property," Mr. Garcia
said. "We believe that this strategic  acquisition  brings core  technology that
will  allow us to  compete  more  effectively  and  begin to  participate  in an
estimated  addressable  international market consisting of 8,000 potential sites
and representing  $250 million in annual sales. Our revised  financial  guidance
for 2005 incorporates the commencement of this business activity."

The Company's  operating income margin increased to 15% compared with 10% in the
prior  year  quarter.  "We must keep our eyes on our  operating  margin  because
average gross  margins  fluctuate  from quarter to quarter  depending on the mix
between  products sold directly and through  distributors,  and gross margin may
not be the final indicator of the profit generation  capability of the Company,"
Mr. Garcia said. He added that "the Company expects to achieve operating margins
of at least 20 percent in 2006 and beyond." IRIS has now secured distribution in
50 countries, all through distributors, except in France where the company sells
directly to end-users through its IRIS Diagnostics  France SARL, based in Paris,
France.
                                     (MORE)


                                       2



Net  revenues  for the first  quarter  ended Mar.  31,  2005,  rose 49% to $14.0
million,  compared with $9.4 million in the  corresponding  quarter of 2004. Net
income  amounted to $1.3  million,  or $0.08 per basic share  ($0.07 per diluted
share), on 16.2 million basic shares  outstanding (17.3 million diluted shares),
compared with net income of $529,000,  or $0.04 per basic and diluted share,  on
12.1 million basic and 13.8 million diluted shares  outstanding during the first
quarter of 2004.

The IN VITRO  diagnostics  segment  revenues grew  approximately  57% during the
first  quarter.  The  international  sector  of this  segment  continues  to get
stronger,  and  represented  approximately  31%  of  the  IN  VITRO  diagnostics
segment's  first quarter  revenues.  "We are also pleased to report that revenue
from  consumables,  supplies and services is growing and  represented 49% of the
first  quarter  segment  revenues  and  approximately  41% of  our  consolidated
revenues over the same period," Mr. Garcia stated.  "Instrument bookings for the
first quarter 2005 are stronger than  anticipated,  and our  consumable  revenue
growth should continue to accelerate during 2005."

Revenues from StatSpin, the Company's small laboratory devices subsidiary,  were
$2.3  million  for the first  quarter,  up from  $2.0  million  in the  year-ago
quarter, an 18% increase.

IRIS' gross profit margin was 49% in the first  quarter  versus 50% in the prior
year quarter,  primarily due to stronger sales of instruments versus consumables
and service and increased  international sales of iQ200 Microscopy Analyzers and
related consumables through distributors at lower margins.

As of Mar. 31, 2005,  IRIS had $13.4  million in cash on hand and net  operating
loss tax carry-forwards of $16 million available for use in future years.

REVISED 2005 GUIDANCE:

         o        PROJECTED  REVENUE  GROWTH  INCREASED  TO AT LEAST 35% FROM AT
                  LEAST 25%
         o        PROJECTED EARNINGS PER SHARE OF $0.30 - $0.35

"Because of these results,  we are increasing our guidance to reflect the strong
demand that we are experiencing for the iQ200 Analyzer and the recently released
iQ200 Sprint Analyzers," Mr. Garcia said.  "During 2005, we expect  consolidated
revenues  to grow at least 35% over 2004 and  earnings  to grow to $0.30 - $0.35
per share, on estimated diluted shares of approximately 18.3 million.  Free cash
flow will begin to grow at a significant rate in the second half of the year and
we expect further escalation in 2006."

THE COMPANY WILL HOLD A CONFERENCE CALL WITH MEMBERS OF THE INVESTMENT COMMUNITY
AT  11:00  A.M.   EASTERN  TIME  TODAY.   TO  PARTICIPATE  IN  THE  CALL,   DIAL
1-800-817-2743  APPROXIMATELY  10 MINUTES BEFORE THE CALL IS SCHEDULED TO BEGIN.
INTERNATIONAL  CALLERS  SHOULD DIAL  913-981-4915.  A WEBCAST OF THE CALL CAN BE
ACCESSED AT www.proiris.com OR AT www.vcall.com.

THE COMPANY

IRIS International,  Inc.  (www.proiris.com) is a leader in automated urinalysis
technology with systems in major medical institutions  throughout the world. The
Company's  newest  generation  iQ(R)200  Automated  Urine  Microscopy  Analyzer,
utilizing image flow cytometry,  patented Automated Intelligent Microscopy (AIM)
technology and neural network-based particle recognition, achieves a significant
reduction in the cost and  time-consuming  steps involved in manual  microscopic
analysis.  The  Company's  StatSpin(R)  subsidiary,  based  in  Norwood,  Mass.,
manufactures  innovative  centrifuges  and  blood  analysis  products.  Advanced
Digital  Imaging  Research,  LLC  (ADIR),  based  near  Houston,  Texas,  is the
Company's imaging research and development subsidiary.


                                     (MORE)


                                       3



SAFE HARBOR PROVISION

This news release contains forward-looking  statements made in reliance upon the
safe harbor provisions of the Private Securities  Litigation Reform Act of 1995.
Forward-looking  statements include, but are not limited to, the Company's views
on future commercial  revenues,  market growth,  capital  requirements,  and new
product introductions, and are generally identified by phrases such as "thinks,"
"anticipates,"  "believes,"  "estimates,"  "expects,"  "intends,"  "plans,"  and
similar  words.   Forward-looking   statements  are  not  guarantees  of  future
performance and are inherently  subject to uncertainties and other factors which
could  cause  actual  results  to  differ  materially  from the  forward-looking
statement. These statements are based upon, among other things, assumptions made
by, and information currently available to, management,  including  management's
own knowledge and assessment of the Company's industry,  competition and capital
requirements.  Other factors and  uncertainties  that could affect the Company's
forward-looking  statements  include,  among other things,  the  following:  the
acceptance by customers of our new iQ(R)200  product  platform,  our substantial
expansion  of  international  sales  and  our  reliance  on key  suppliers,  the
potential  need  for  changes  in  long-term  strategy  in  response  to  future
developments;  future advances in diagnostic testing methods and procedures,  as
well as potential  changes in government  regulations  and healthcare  policies,
both of which could  adversely  affect the economics of the  diagnostic  testing
procedures  automated by the Company's products;  rapid technological  change in
the microelectronics and software  industries;  and increasing  competition from
imaging and non-imaging based in-vitro diagnostic  products.  The Company refers
interested  persons to its most recent  Annual Report on Form 10-K and its other
SEC filings for a description of additional  uncertainties  and factors that may
affect  forward-looking  statements.  The Company  assumes no duty to update its
forward-looking statements.

                                 (TABLES FOLLOW)


                                       4



                            IRIS INTERNATIONAL, INC.
                      CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (unaudited)

                                                           For the three months
                                                                   ended
    (in thousands except for per share amounts)                  March 31,
- --------------------------------------------------------   --------------------
                                                             2005        2004
                                                           --------    --------

Sales of IVD instruments ...............................   $  5,939    $  2,543
Sales of IVD consumables and service ...................      5,699       4,672
Sales of small laboratory devices and supplies .........      2,326       1,974
Royalty and license revenues ...........................       --           186
                                                           --------    --------

Net revenues ...........................................     13,964       9,375
                                                           --------    --------

Cost of goods - IVD instruments ........................      3,593       1,864
Cost of goods - IVD consumables and service ............      2,315       1,800
Cost of goods - small laboratory devices and supplies ..      1,162       1,007
                                                           --------    --------

Cost of goods sold .....................................      7,070       4,671
                                                           --------    --------

Gross margin ...........................................      6,894       4,704
                                                           --------    --------

Marketing and selling expenses .........................      2,391       1,490
General and administrative expenses ....................      1,394       1,193
Research and development, net ..........................      1,083       1,053
                                                           --------    --------

Total operating expenses ...............................      4,868       3,736
                                                           --------    --------

Operating income .......................................      2,026         968

Other income (expense):
   Interest income .....................................         53          11
   Interest expense ....................................         (5)        (90)
   Other (expense) income ..............................         44          (7)
                                                           --------    --------

Income before income taxes .............................      2,118         882

Provision for income taxes .............................        847         353
                                                           --------    --------

Net income .............................................   $  1,271    $    529
                                                           ========    ========

Basic net income per share .............................       0.08        0.04
                                                           ========    ========

Diluted net income per share ...........................   $   0.07    $   0.04
                                                           ========    ========

Basic - average shares outstanding .....................     16,218      12,051
                                                           ========    ========

Diluted - average shares outstanding ...................     17,294      13,846
                                                           ========    ========


The  accompanying  notes are an integral  part of these  consolidated  financial
statements.


                                     (MORE)


                                       5



                            IRIS INTERNATIONAL, INC.
                           CONSOLIDATED BALANCE SHEETS
                                 (in thousands)

                                                          MAR. 31,     DEC. 31,
ASSETS                                                      2005         2004
                                                          --------     --------
Current assets:
Cash and cash equivalents ............................    $ 13,428     $ 12,839
Accounts receivable, net .............................      10,290        8,847
Inventories, net .....................................       7,012        7,834
Prepaid expenses and other current assets ............         447          381
Investment available for sale ........................         121          198
Deferred tax asset ...................................       3,650        3,650
                                                          --------     --------

   Total current assets ..............................      34,948       33,749
Property and equipment, at cost, net .................       3,896        3,880
Goodwill .............................................         189          189
Software development costs, net ......................       1,760        1,930
Deferred tax asset ...................................       4,824        5,665
Inventories - long term portion ......................         489          290
Other assets .........................................       3,111        2,433
                                                          --------     --------
Total assets .........................................    $ 49,217     $ 48,136
                                                          ========     ========

LIABILITIES AND SHAREHOLDERS' EQUITY
Current liabilities:
Accounts payable .....................................    $  3,287     $  4,258
Accrued expenses .....................................       2,661        3,398
Deferred service contract revenue ....................       1,269        1,134
                                                          --------     --------
     Total current liabilities .......................       7,217        8,790

Deferred service contract revenue, long term .........         139          173
                                                          --------     --------

     Total liabilities ...............................       7,356        8,963

Commitments and contingencies

Shareholders' equity:
Common stock, $.01 par value
  Authorized: 50 million shares; issued and
    outstanding: 16,322 shares and 15,962 shares .....         163          159
Additional paid-in capital ...........................      63,545       61,972
Unearned compensation ................................        (274)        (125)
Accumulated other comprehensive income ...............        --             11
Accumulated deficit ..................................     (21,573)     (22,844)
                                                          --------     --------

     Total shareholders' equity ......................      41,861       39,173
                                                          --------     --------
 Total liabilities and shareholders' equity ..........    $ 49,217     $ 48,136
                                                          ========     ========


The  accompanying  notes are an integral  part of these  consolidated  financial
statements.


                                       ###


                                       6