Eleven patients with postoperative abdominal and pelvic lymphoceles underwent percutaneous diagnostic and therapeutic intervention with either needle aspiration or catheter drainage. Although initial sonographic or CT examinations accurately identified these collections, definitive diagnosis required fluid sampling and laboratory analysis for confirmation. Seven pelvic and two retroperitoneal lymphoceles demonstrated a gross appearance and composition different from two lymphatic collections in the upper peritoneum. Nine patients underwent catheter drainage; two were managed by needle aspiration alone. Duration of catheter drainage was 4-120 days, substantially longer than is customary for standard fluid collections. Nine of 11 patients were cured by percutaneous aspiration or drainage alone. Bacterial colonization developed in three persistently draining lymphoceles. However, no clinical sepsis or bacteremia occurred. In another patient with persistent high-volume lymphatic output, sclerotherapy with tetracycline instillation was successful in rapidly closing the lymphatic fistula. Percutaneous drainage is a safe, effective procedure for drainage of postoperative lymphoceles.