A 69-year-old man was admitted for resection of rectal adenocarcinoma diagnosed by colonoscopy. Preoperative computed tomography scan and abdominal ultrasonography revealed bilateral renal tumors measuring up to 2 and 2.8 cm in largest diameter, respectively. The patient underwent partial colectomy and bilateral partial nephrectomy. Microscopically, rectal adenocarcinoma penetrated the submucosa, without invasion of the muscularis propria. Both renal tumors were clear cell renal carcinomas of Fuhrmann nuclear grade 2. To our knowledge, this is the first case of synchronous adenocarcinoma of the rectum and bilateral clear cell renal cell carcinoma described in the literature to date.