We report four cases of mucin-producing carcinoma of the gallbladder (three papillary adenocarcinomas and one mucinous carcinoma), with an emphasis on imaging features. Our findings suggest that when a papillary protrusion or thickened wall, including cystic areas and/or calcifications, is seen radiologically in the enlarged gallbladder, mucin-producing carcinoma of the gallbladder should be included in the differential diagnosis.