Introduction. Colon atresia is a rare form of congenital bowel obstruction. In scientific literature, there are isolated publications devoted to colon atresia, and only some authors discuss the membranous form of atresia.Material and methods. The article describes a rare clinical case of an incomplete colon membrane in an infant. At the age of 11 months, the child developed symptoms of acute intestinal obstruction. Irrigography was performed; Hirschsprung’s disease was suspected. At the first stage, the child was taken a floor-by-floor biopsy of the colon, and an ileostomy was put. Visually, Hirschsprung’s disease seemed to be present; however, histological examination turned aside this diagnosis. Given this, the colon membrane was suspected. Partial resection of the altered part of the sigmoid colon was performed with good clinical effect. Histological examination revealed an incomplete serous-muscular membrane of the colon.Conclusion. Colon atresia is a rare disease that presents a serious problem for diagnosis and treatment. Preoperative morphological verification of the diagnosis is important, even in case when Hirschsprung’s disease seems obvious. Preoperative diagnostics is important because surgical tactics may be considerably different in colon local lesions.