Gallstone obstruction of the cystic duct, resulting in chronic cholecystitis and pressure necrosis leads to the formation of biliobiliary fistula (BBF). We herein reported a case of Mirizzi syndrome (MS) with an unusual type of BBF (Corlette type I) that was successfully managed by a staged treatment strategy. The patient was diagnosed with a solitary gallstone, marked atrophy of the gallbladder, and BBF and underwent mucosal incineration of the atrophic gallbladder and simple closure, followed by extirpation of gallbladder. Although an optimal treatment strategy has not yet been established for MS with BBF because of its rarity and anatomical variations in fistulas, the current treatment strategy may be applicable. In conclusion, clinicians need to carefully diagnose and evaluate chronic cholecystitis in MS with BBF and adopt an optimal treatment strategy to avoid the complication associated with this disease.