Retrospective comparative analysis of treatment of 158 patients with complicated forms of acute appendicitis in whom surgical intervention was started with diagnostic laparoscopy has been carried out. In 69 (43.7%) patients diagnostic laparoscopy was completed with laparoscopic appendectomy, in the remaining 89 (56.3%) patients conversion to a small or wide open surgical access was necessary. Laparoscopic approach allowed adequately sanitizing abdominal abscesses in cases of local and diffuse peritonitis in 67 (98.6%) patients. The presence of diffuse peritonitis (n=9) and periappendicular abscess (n=13) was considered as an indication for conversion. Authors considered that inflammation of the base of the appendix, tiflitis phenomena, as well as a base diameter of more than 1.5 cm are high-risk conditions for appendiceal ligation and are indications for conversion to open approach. Results of treatment were assessed by the type and the number of postoperative complications, reoperations, length of hospital stay, and others. There were not observed deaths in the study. The collected data indicated that the incidence of postoperative complications in patients with conventional appendectomy (28.1%) is much higher than that in patients with laparoscopic appendectomy (4.3%). The authors concluded that laparoscopy has high diagnostic and therapeutic possibilities in patients with complicated forms of acute appendicitis.