Caudal duplication syndrome is a very rare congenital deformity. A 13-year-old boy was born with duplicated colon-rectum and anus, diphallus, hydronephrosis of left kidney with megaureter, double bladders and urethras, and vertebral abnormalities. Multiple-stage correction was performed to remove the duplicated colon and the mucosa of the duplicated rectum. A new colon was reconstructed. The left kidney and megaureter were excised. The septum in the bladders was removed to convert the double bladders into a single bladder. The double phalluses were fused into a single penis. After these staged procedures, the boy is now living a normal life.