Most experienced laparoscopic units suggest a rate of conversion to open cholecystectomy of about 5%. Some failures are predictable preoperatively. We have reviewed the prospective data collected on our first 285 laparoscopic cholecystectomies to provide a basis for advising patients about the likelihood of conversion (failure) if laparoscopic cholecystectomy is attempted. Risk factor analysis was performed to assess the effect on the conversion rate of clinical presentation, preoperative ultrasound features, previous abdominal surgery, and morbid obesity. The overall conversion rate was 4.9%. We identified three preoperative clinical parameters associated with a high risk of failure at laparoscopic cholecystectomy: a contracted gallbladder on ultrasound, gallstone pancreatitis, and a previous history of upper abdominal surgery. Factors that did not predict failure were: an ultrasound report of a thick gallbladder wall, morbid obesity, or acute cholecystitis. It is concluded that laparoscopic cholecystectomy is technically feasible in most patients, but those having the above-mentioned risk factors should be warned of a higher than usual chance of conversion to open cholecystectomy.