The laparoscopic cholecystectomy is now a standard part of general surgical practice. Conversion from a laparoscopic cholecystectomy to an open cholecystectomy is sometimes required. To identify the factors predisposing to conversion, we retrospectively reviewed all patients undergoing a laparoscopic cholecystectomy from December 1991 to June 1996 at Chosun University Hospital. Factors evaluated were age, sex, history of acute cholecystitis, previous abdominal surgery, associated disease, laboratory findings, and thickened gallbladder wall identified by preoperative ultrasound. Conversion to an open cholecystectomy was required in 42(9.0%) of the 465 patients. The most common reason for conversion was the inability to define the anatomy secondary to inflammation or adhesions. Significant predictors of conversion to an open cholecystectomy were increasing age (age over 60 years), presense of associated disease, a thickened gallbladder wall found by preoperative ultrasound, acute cholecystitis, and increased alkaline phosphatase level. Multivariate analysis found a patients age of over 60 years to be an independent predictor of conversion to an open cholecystectomy. An appreciation for these predictors of conversion will allow appropriate planning by the patients, the institution, and the surgeons. Although data are lacking, increasing experience with laparoscopic cholecystectomy has likely resulted in earlier recognition of the need for conversion to an open cholecystectomy with a resultant decrease in morbidity.