Intraoperative cholangiograms and exploration of the common bile duct (CBD) during laparoscopic cholecystectomy are technically more demanding than during open cholecystectomy. This has led to many surgeons using a selective policy for cholangiography. In this study we prospectively assessed whether biliary ultrasound (CBD diameter > or = 6 mm) or one or more abnormal liver function tests (LFTs) performed in the 24 hours preoperatively could predict the need for cholangiography. Forty-five patients were studied (14 male, 31 female), mean age 47.8 years. All patients with one or both tests abnormal preoperatively (19 patients) underwent intraoperative cholangiograms. Seven CBD stones were identified (16%). There was no evidence of CBD stones in patients not undergoing cholangiography at a median follow-up of 18 months. In patients with stones, three underwent open CBD exploration, and four underwent endoscopic retrograde choledochopancreatography (ERCP) and sphincterotomy in the early postoperative period without complications. CBD diameter > or = 6 mm is a useful predictor of CBD stones. These may be treated successfully by postoperative ERCP.