Enteric duplication is a rare congenital anomaly which is commonly encountered in pediatric age group, and is rarely seen in adult patients. Ileum is the most common site of involvement (60%) followed by duodenum, stomach, jejunum, colon and rectum. Here we report a case of a 20-year old female presenting with acute intestinal obstruction, in which an initial diagnosis of Hirschsprung’s disease (HD) was considered and laparotomy, multiple colonic biopsies, appendectomy with loop ileostomy was done. The diagnosis of HD was disproved by presence of ganglionic cells in the colonic wall. Diagnosis of a long duplication, along the entire length of colon, was made when a CECT was done with instillation of contrast through the distal limb of ileostomy. A subtotal colectomy with division of septum between the residual cyst and rectum with colorectal anastomosis was done after a month and closure of ileostomy after another 3 months. The patient recovered well and is asymptomatic in follow-up.