Primary lymphomas of mucosa associated lymphoid tissue （MALT） lymphoma of the gallbladder is exceedingly rare. A 67-year-old man was admitted to our hospital presenting with epigastric pain and vomiting. Abdominal computed tomography （CT） and magnetic resonance cholangiopancreatography （MRCP） revealed dilatation of the gallbladder, thickening of the gallbladder wall, and biliary sludge formation in the gallbladder. Thus, the patient was diagnosed with acute cholecystitis and underwent laparoscopic cholecystectomy. Microscopically, we noted that lymphoid cells had infiltrated the mucosa of the gallbladder and formed a lymphoepithelial lesion （LEL）. On polymerase chain reaction analysis, the reconstituted immunoglobulin heavy chain was detected. Therefore, a diagnosis of MALT lymphoma of the gallbladder was made. We report a case diagnosed with primary MALT lymphoma of the gallbladder after cholecystectomy.