<ARTICLE>                     5
<CIK>                         0000779282
<NAME>                        DIANON SYSTEMS, INC.
<MULTIPLIER>                  1,000
<CURRENCY>                    U.S. DOLLARS

                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>               DEC-31-1999
<PERIOD-START>                  APR-01-1999
<PERIOD-END>                    JUN-30-1999
<EXCHANGE-RATE>                                1
<CASH>                                         7,945
<SECURITIES>                                       0
<RECEIVABLES>                                 17,393
<ALLOWANCES>                                   1,010
<INVENTORY>                                    1,035
<CURRENT-ASSETS>                              27,402
<PP&E>                                        15,485
<DEPRECIATION>                                 9,929
<TOTAL-ASSETS>                                48,508
<CURRENT-LIABILITIES>                          7,422
<BONDS>                                            0
<PREFERRED-MANDATORY>                              0
<PREFERRED>                                        0
<COMMON>                                          68
<OTHER-SE>                                    34,925
<TOTAL-LIABILITY-AND-EQUITY>                  48,508
<SALES>                                       19,053
<TOTAL-REVENUES>                              19,053
<CGS>                                         10,896
<TOTAL-COSTS>                                 10,896
<OTHER-EXPENSES>                               6,603
<LOSS-PROVISION>                                   0
<INTEREST-EXPENSE>                                76
<INCOME-PRETAX>                                1,621
<INCOME-TAX>                                     673
<INCOME-CONTINUING>                              948
<DISCONTINUED>                                     0
<EXTRAORDINARY>                                    0
<CHANGES>                                          0
<NET-INCOME>                                     948
<EPS-BASIC>                                   0.14
<EPS-DILUTED>                                   0.14