SUMMARY A detailed pathological and psychosocial study was made of all postperinatal (8 days-2 years) deaths in Sheffield during a 2-year period. The cause of death was classified from the point of view of possible prevention. Of the total of 65 deaths, 35 were unpreventable after the perinatal period, but 9 might have been preventable before birth. Of the 30 other deaths, 20 had evidence of possible treatable disease, and for the majority of these adverse social factors could be identified.