Introduction: Cancer of the gallbladder is a serious diagnostic and therapeutic problem. According to the literature, 30% of cases are not confirmed before surgery. Other cases are detected incidentally by histopathology. Clinical trials and meta-analyses show that incidental gallbladder cancer (iGBC) occurs in 0.19% to 2.8% of patients after cholecystectomy.The aim of the study was to analyse the incidence and severity of iGBC in cholecystectomy procedures performed in the Surgical Department at the 4th Military Teaching Hospital in Wroclaw in the years 1990-2014.Material and methods: In the years 1990-2014 a total of 7,314 cholecystectomies were performed in the Surgical Department because of cholecystolithiasis: 6,145 using the laparoscopic approach (84.02%), 867 were performed as open... surgery (11.8%) and 302 cases required conversion (5.1%). In this group, 5,214 of the patients were women (71.3%) and 2,100 were men (28.7%). The average age of patients was 54.7 years.Results: We found 64 iGBC cases which were confirmed by histopathology. This represented 0.87% of all cases. In this group, 50 patients were women (78.1%) and 14 were men (21.8%), with an average age of 67.1. Of this group, 40 patients underwent a classic cholecystectomy, while 24 underwent laparoscopic procedures, out of which 13 cases ultimately required traditional surgery. The histopathology showed 15 carcinomas that were classified as G1 (23.4%), 28 – were G2 (43.75%) and 21 – were G3 (32.8%).Conclusions: IGBC detected after a cholecystectomy due to cholecystolithiasis is a rare disease. We found iGBC in 0.87% of cases, which is on a comparable scale to the world literature. In the case of cancer, we frequently found it necessary to convert to an open surgical procedure. This cancer is more common in women and in people over 60-years of age.