Two cases of gallbladder carcinoma occurring in intramural diverticulosis (adenomyomatosis) are reported. The first was adenocarcinoma associated with cholesterolosis without gallstone formation. The second was squamous cell carcinoma. Four other carcinomas developing on diverticulosis were reported in the literature, none of them being squamous cell carcinoma. Our cases and those of the literature show that diverticulosis, a benign condition, can be associated with carcinoma which can make the pathological diagnosis difficult.