Thirty patients with obstructive jaundice with plasma bilirubin values greater than 200 mumol/L were randomized at the time of percutaneous transhepatic Cholangiography to undergo immediate or delayed surgery. The patients who had preoperative percutaneous transhepatic biliary drainage (PTBD) for 13.8 +/- 5.8 days had fewer surgical complications than did patients who underwent immediate surgery (p less than 0.02), although when the complications of PTBD were included this advantage was diminished. Immediate surgery caused greater deterioration of renal function as measured by plasma urea, plasma B 2-microglobulin, phosphate clearance, uric acid clearance, and maximal concentrating ability than occurred after PTBD or delayed surgery. The improvement in phosphate clearance that followed PTBD was sustained through delayed surgical treatment, indicating better tubular function in these patients. This article supports the concept that preoperative PTBD will reduce surgical morbidity and will result in less renal impairment than will immediate surgery. However, the morbidity rates of the PTBD procedure will preclude its wide use.