Computed tomography and ultrasonography are effective methods for diagnosis and localization of renal and perinephric abscesses. In patients with clinical suspicion of sepsis, diagnostic needle aspiration of these lesions can be safely performed extraperitoneally by using sectional imaging for guidance. When an abscess is confirmed, small catheters can be introduced percutaneously via the diagnostic aspiration route to provide immediate decompression as well as continuous and definitive drainage without need for surgery. In 8 cases so treated, there were no major complications, deaths, or recurrences. These results, obtainable without the risks of surgery, indicate that patients with renal or perinephric abscesses should be offered a trial of percutaneous drainage as a definitive method of therapy. Those cases not amenable to percutaneous drainage, or those in which the procedure has failed, can then be drained surgically. Percutaneous abscess drainage is widely applicable because it can be performed in any uroradiologic facility with access to sectional imaging.