Obesity alone and rapid weight loss induced by bariatric surgical procedures are both recognized risk factors for the development of cholelithiasis. The advisability of performing routine concomitant cholecystectomy with bariatric surgery has been controversial. This prospective clinical study was performed to determine if preoperative ultrasonography, preoperative cholescintigraphy and intraoperative surgical findings could help determine which patients would benefit from concomitant cholecystectomy. Eighteen morbidly obese patients undergoing bariatric surgery were studied preoperatively with gallbladder ultrasonography and cholescintigraphy. All patients had a description of intraoperative findings. Gallbladders were removed routinely and examined pathologically. Sixty percent of patients in this study had abnormal gallbladder pathology. Preoperative ultrasonography and/or cholescintigraphy was inaccurate at predicting reliably those patients who would benefit from cholecystectomy concomitant with gastric-restrictive surgery. Intraoperative findings other than palpable gallstoneswere also unreliable.