Adenomyomatosis of the gallbladder (AMG) is not very common, however inherited and degenerative disease of the gallbladder with premalignant to malignant potential through metaplasia, occurring especially in a segmental form at higher-age patients, although the fundal form occurs more often. It can be found in 2-8.7% of resected gallbladder after cholecystecomy. In some cases, but extremely rarely, it has been found also in extrahepatic bile ducts. Correct pre-operative diagnosis does not exceed 30%, as it is often considered as an acute or chronic inflammatory gallbladder disease, same as in our case report. Disease development from the clinical point of view is mostly asymptomatic, where again the cholecystectomy is recommended.