Seminal vesicle agenesis cannot be an isolated finding, and it is usually seen in two situations. The first situation may be attributed to an insult of the mesonephric duct during embryogenesis and is generally associated with ipsilateral or bilateral agenesis or ectopia of the vas deferens. If the insult occurs before 7 weeks of gestation, patients will suffer ipsilateral renal agenesis as in our case. The second situation of bilateral or unilateral seminal vesicle agenesis is also associated with ipsilateral agenesis of the vas deferens, but the kidneys are normal. A patient with Zinner syndrome is usually a male in the 3rd or 4th decade with a triad of unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction.