Atresia of the colon is a rare anomaly with an incidence of between 1:20,000 and 1:66,000 live births being reported. Hirschsprung's disease association with Colonic atresia is usually diagnosed after several failures of intestinal anastomoses. We herein report one of the first patients in the literature diagnosed before a therapeutic challenge. A 2-day-old female was admitted with severe abdominal distention, bilious vomiting and failure to pass meconium. A distended abdomen accompanied by hypoactive bowel sounds was also observed. Abdominal X-ray revealed increased intestinal gas, mainly in the colon. Type IIIa atresia of the colon at the level of the splenic flexure was found at laparotomy. A temporary double-barrel colostomy was completed, and she was discharged from hospital on the tenth day after operation without any complications. At the age of 3 months, due to the aspect of the distal colon, a rectal biopsy was performed and aganglionosis was confirmed. The combination of intestinal aganglionosis and colonic atresia is extremely rare. The concomitance of colonic atresia and aganglionosis is calculated to be in 1 in 10 million live births. Wilson, et al. claims that 80 percent of infants with colonic atresia have associated gastrointestinal anomalies. These defects include rotation and fixation anomalies. However, aganglionosis and intestinal neuronal dysplasia should be taken into account as well. When both diseases are combined, the etiology is still uncertain and several etiologies have been suggested. The association should be suspected in all cases of colonic atresia and rectal biopsies are advocated at the primary operation in patients with atresia of the colon.