THIS REPORT is to record the occurrence of the death of an infant with congenital aganglionic megacolon which is attributed to the development of pseudomembranous enterocolitis. It is believed that this combination of events has not been previously reported. The features of the case reported herein reflect the diagnostic difficulties of congenital megacolon in infancy and the alarming rapidity with which an apparently minimally ill infant can progress into the moribund state. Prior case studies, 1,2 have documented that signs and symptoms of intestinal obstruction develop in congenital megacolon. In large measure, the threat to these infants' lives is due to the development of a nonspecific enterocolitis. 3 The latter observation, as well as an increased incidence of pseudomembranous enterocolitis in postoperative adult patients with clinical evidence of intestinal obstruction, 4 suggest that pseudomembranous enterocolitis might be a reasonably expected development in certain infants with congenital megacolon. Report of a