Thirty-five patients with symptomatic gallbladder disease were prospectively evaluated by ultrasound the day before laparoscopic cholecystectomy. Diminished gallbladder function and wall thickening were significantly associated with increased technical difficulty of the operation (Student's t-test, P < 0.001). There was no association between gallbladder volume or number of calculi and operative difficulty. Dilated common bile ducts were detected by ultrasound in five patients (14%) and bile duct calculi in two patients (6%). Ultrasound findings can be used as predictors of potential operative difficulties when selecting patients for laparoscopic cholecystectomy. Ultrasound should be used as an initial screening investigation to detect common bile duct dilatation and calculi.