下腔靜脈後輸尿管為一罕見之先天性血管發育異常。我們報告兩例下腔靜脈後輸尿管合併尿路感染及阻塞症狀，經由電腦斷層檢查後確立診斷。對大多數有症狀之病患而言，下腔靜脈後段之輸尿管切除再重接是一簡單又有效之手術治療方法。

Retrocaval ureter is relatively uncommon congential anomaly. We report 2 cases of retrocaval ureter with presentations of urinary obstruction and infection. The diagnosis was established after computed tomography examination. Segmental resection of the retrocacal portion of the ureter with end-to-end anastomosis is an easy and effective therapy in most symptomatic patients.