Colonic atresia (CA) is a very rare cause of intestinal obstruction, and little information has been available about the management and predictors of outcome. A retrospective clinical trial was performed to delineate the clinical characteristics of CA with special emphasis on surgical treatment and factors affecting outcome. Children with CA who were treated in our department between 1977 and 1998 were reviewed: 14 boys and 4 girls aged 1 day to 5 months. All but 2 referred patients and 1 with prenatal diagnosis presented with intestinal obstruction. Plain abdominal X-ray films showed findings of intestinal obstruction in 14 cases; a barium enema demonstrated a distal atretic segment and microcolon in 4. The types of atresia were IIIa (n=9), I (n=6), and II (n=3). Type IIIa atresias were located proximal to the splenic flexure (n=8) and in the sigmoid colon (n=1), type I atresias were encountered throughout the colon; and all type II atresias were proximal to the hepatic flexure. Associated anomalies were multiple small-intestinal atresias (MSIA) (n=4), gastroschisis (GS) (n=2), pyloric atresia (n=1), Hirschsprung's disease (n=1), and complex urologic abnormalities (n=1). The initial management was an enterostomy in 15 patients (83%), including 2 referred and 2 with GS, and primary anastomosis in the remaining 3 (17%). Secondary procedures were the Santulli operation (n=2), colostomy closure and recolostomy followed by a Swenson operation (n=1), sacroabdominoperineal pull-through (n=1), and colostomy closure (n=1). Leakage was encountered in all primarily anastomosed patients. The overall mortality was 61%. Deaths occurred in patients with associated major anomalies (GS 2, MSIA 3, pyloric atresia 1) (55%) and in 3 patients who were initially managed by primary anastomosis (27%). Two additional patients died of sudden infant death syndrome (18%). Type I atresia was more common than in previously reported series and was associated with proximal multiple atresias. The initial management of CA should be prompt decompression of the intestine by an ostomy procedure, preferably end- or double-barrel. The type of surgery (primary anastomosis without prior colostomy) and associated abnormalities are the major determinants of poor outcome.