Congenital Unilateral Agenesis is defined as the complete absence of one kidney due to failure of the wolffianduct to give off a corresponding ureteric bud, and have not to be confused with renal hypoplasia, aplasia, chronicatrophy, or fusion anomaly. Usually this condition has no clinical symptom and is discorved during a routineurographic study for some other genitourinary diseases. So the reported cases are uncommon but not rare in autopsyseries. This situation occurs more on the left side, and more in males. We have experienced 2 cases of CongenitalUnilateral Renal Agenesis proved by Radiologically and Surgically, and report with brief review of theliteratures.