Primary adenocarcinomas of the small bowel are rare. Because of their rarity, non-specific symptoms and diagnostic difficulty, small bowel tumors are often diagnosed and treated late in their course. The diagnostic difficulty is increased when these tumors arise in association with primary synchronous tumors of the colon. We present a case of a 17-year-old female who was evaluated for anemia and bleeding per rectum. Colonoscopy revealed multiple colonic polyps. Intraoperatively, she was surprisingly found to be having a synchronous jejunal growth apart from multiple colonic polyoid lesions. Total colectomy was performed along with resection of jejunal growth. Histopathology of colonic specimen revealed multiple polypoid projections with one polyp showing adenocarcinoma and rest severe dysplasia. Histopathology of jejunal growth revealed poorly-differentiated adenocarcinoma. Very rarely, cases have been reported in literature, where the primary adenocarcinoma of the jejunum developed synchronously with colonic adenocarcinoma, and both treated surgically on the same occasion.