We reviewed 15 years' experience with childhood trauma at two hospitals in different cities, one a city hospital, the other a children's hospital, to learn the extent, circumstances, presentations, and consequences of major blunt abdominal trauma due to child abuse. Some 10,000 children admitted to these hospitals for treatment of injuries from 1972 through 1986 provided the basis for the study; the incidence and severity of pediatric trauma at the two hospitals was similar, in that 13% of the visits to both hospitals' emergency rooms were for trauma, of which 5% resulted in admission. Major blunt abdominal trauma due to child abuse accounted for 22 of these cases, six at the former, 16 at the latter, and represented less than 0.50% of all abused children seen at both institutions. The average age was 24 mo; 14 were boys and eight were girls. In only two instances was the family unit intact; in both, the child was abused by the babysitter. Otherwise, the father, or the mother's "boyfriend," was responsible. Overall mortality was 45%, and was related both to type of injury and presenting signs. Of one who presented with an epigastric mass due to a pancreatic hematoma, none died; the pseudocyst which subsequently developed resolved on bowel rest and TPN. Of three who presented with bilious vomiting due to duodenal hematoma, none died; one required operative evacuation. Of five who presented with peritonitis due to duodenojejunal rupture, one died; this child presented greater than 24 hr following injury in profound septic shock. Of three who presented with hypovolemia due to moderate hemorrhage, none died; the former two were managed conservatively.(ABSTRACT TRUNCATED AT 250 WORDS)