Duplication of gut presenting as perforation, peritonitis in an adult is a very rare clinical presentation. Here we report a case of an adult female patient in generalized peritonitis was caused by perforation of tubular communicating, duplicated, Ileal loop which rotated at its attachment with main ileum. This condition was managed by performing laparotomy, excision of the duplicated gut segment followed by end to end ileoileal anastomosis. KEYWORDS: Duplication of small intestine, Obstruction and perforation, Resection and anastomosis.CASE REPORT: A 32 yrs. old female presented in surgical OPD with the history of generalized abdominal pain, gradual distension and vomiting off and on for the last 3-4 days. She had been suffering from episodes of these symptoms for past couple of months, suggestive of sub-acute intestinal obstruction. However for last few days, these symptoms were aggravated.Patient had been empirically put on ATT by clinicians whom she had been consulting before coming to our hospital. Patient had undergone laparotomy about 8 years ago for perforated appendix. Patient appeared quite ill, dehydrated with tachycardia tachypnea and mild fever.Physical examination, revealed distended abdomen with tenderness and guarding all over. Rebound tenderness was also present. No hepatosplenomegaly was detected. P/V and P/R examination were within normal limits. A right paramedian scar from previous surgery was present.Hematological profile revealed normal study. X-ray abdomen erect view showed multiple Air fluid levels. USG study of abdomen showed mesenteric thickening with mild fluid and dilated bowel loops. She was taken up for Exploratory Laparotomy after correcting her dehydration.Abdomen was opened through mid-line incision which revealed dilated small bowel loops with free fluid. Exploration revealed about one feet long tubular, dilated and duplicated gut which had rotated upon its own axis where it was joining with the main gut, communicating at both proximal and distal ends, causing obstruction and perforation. [Fig. 1, Fig. 2]. The segment had no independent mesentery. It derived it's vascularity from the main ileal wall segment with which it was communicating (as shown by a hand inserted in the intervening empty space between the two segments in the Fig. 2). This segment was about 2.5 ft. away proximal to ileocecal junction. This duplicated gut segment was resected and an end to end ileoileal anastomosis was done. No evidence of abdominal Koch's was detected.Her post-operative period remained uneventful and she was discharged fifteen days after surgery.HPE Report: Revealed duplication of small gut with all three layers. No evidence of heterotopia, dysplasia or tuberculosis was found.