Laparoscopic cholecystectomy is one of the most frequently performed surgical procedures. In spite of the progress in diagnostic methods and surgical techniques, some operations have to be converted into the laparotomy.The aim of the study was to analyse the reasons and determine predictive factors for conversion.Material and methods. The study was comprised of 765 patients were operated on with the laparoscopic procedure due to cholelithiasis in Franciszek Raszeia Hospital in Poznań from 1 January 1996 to 31 January 2007. Conversion was performed in 106 cases. Retrospective researches were based on descriptions of operations and case records. Statistical comparisons were performed by means of Mann-Withney, t-Student and Fisher tests (p<0.05).Results. The percentage of conversion was 13.85%. The following reasons for conversion were observed: uncertain anatomy 25.47%, dense adhesions 25.47%, inaccessible gall-bladder 9.43%, bleedings 9.43%, inflammatory-purulent lesions of the gallbladder 12.26%, lost gallstones 3.77%, bile leakage 3.77%, failed pneumoperitoneum 2.83%, suspicion of cancer 1.88%, anaesthetic difficulties 1.88, choledocholithiasis 1.88%, equipment failure 1.88%. The statistically significant risk factors for conversion were the following: operations performed by less experienced surgeons (p<0.0001), BMI≧30 (p<0.0001), results above the norm - AspAT (p=0.0288), AlAT (p=0.0013), bilirubin (p<0.0001), WBC (p<0.0001) and ultrasound results - thickened gallbladder wall (p<0.0001), gall-bladder bigger than 10 cm (p=0.0762), hyperechogenic bile (p=0.0003). Conversions were performed more often in the case of men (p=0.0001), people aged over 50 years (p=0.0001) and illness duration over 5 years (p=0.0007). Early postoperative complications occurred in 7 cases (0.91%). Late postoperative complications occurred in three patients (0.39%).Conclusions. A preoperative analysis of risk factors enables selection of a group of patients with higher probability of conversion during the laparoscopic cholecystectomy. A higher number of conversions decreases the number of complications after a laparoscopic cholecystectomy.