Inverted Y duplication of the ureter is a rare anomaly. We report on a 24-year-old man who presented with urolithiasis and azoospermia in a solitary functioning kidney with an inverted Y ureteral duplication. To our knowledge our case represents the first documentation of ectopic emptying of 1 limb of the inverted Y ureter into the seminal vesicle. The embryology and management of this complex case are discussed.