OBJECTIVE--To assess the value of the second neonatal examination as a medical surveillance procedure. DESIGN--Prospective survey of routine neonatal examinations and the abnormalities identified during 8 March-30 June 1988. SETTING--Maternity unit with an annual birth rate of 5700. SUBJECTS--For first neonatal examination: 1795 babies born in the unit during the 115 day observation period. For second routine examination: 1747 babies (97.3%) discharged from postnatal ward. MAIN OUTCOME MEASURES--Missed abnormalities (present but not previously noted); minor abnormalities (superficial infection or trivial or transient abnormalities not requiring intervention); and important abnormalities (unlikely to have been present at first examination but requiring intervention). RESULTS--An abnormality was detected in 158 (8.8%) infants on first neonatal examination. 1428 (79.6%) babies had a routine second examination, which disclosed 63 previously undetected abnormalities. Of these, seven (11%) would have been present on first examination, 49 (78%) were considered minor, and seven (11%) important--the most consequential being dislocatable hips (four infants). Thus an important finding was detected by only 0.5% of second examinations. CONCLUSIONS--A second thorough examination in the early neonatal period cannot be justified as a screening procedure. A repeat examination of the hips alone in the first week of life is necessary.