Reliable predictive factors for conversion of laparoscopic cholecystectomy (LC) would be extremely useful in the preparation and planning of admission for patients with symptomatic cholelithiasis. Data from 783 patients in whom LC was attempted in a university clinic from June 1990 to December 1995 were retrospectively analyzed. The aim of this study was to determine preoperative indicators that can be useful for predicting conversion to open cholecystectomy (OC). Conversion was required in 58 (7.4%) patients, of which 48 (83%) were elective and 10 (17%) emergency. Factors evaluated were age, sex, obesity, duration of gallstone disease, co-morbid factors, indication for surgery, previous abdominal surgery, fever, physical examination findings, white blood cell (WBC) count, liver function tests, ultrasound findings, and the experience of the surgeon. Acute cholecystitis, rigidity in the right upper abdomen, fever, thickened gallbladder wall on ultrasonography, elevated alkaline phosphatase (ALP), liver transaminases and the WBC count were significant predictors of conversion in the univariate analysis. Multivariate logistic regression analysis on these significant predictors showed that acute cholecystitis [odds ratio (OR) = 3.12], thickened gallbladder wall on ultrasonography (OR = 3.75), elevated ALP (OR = 2.23), and WBC count (OR = 3.69) were jointly significant.