Carcinosarcoma of the gallbladder is a rare cancer characterized by presence of a carcinomatous and a sarcomatous component. In our work, we report the case of a 66-year-old male patient, presenting with isolated abdominal pain evolving for more than 6 months. contrast-enhanced computed tomography enabled identification of a gallbladder mass, invading liver, duodenum and abdominal wall. A cholecystectomy, extended to liver, duodenum and abdominal wall was performed. The final diagnosis of gallbladder carcinosarcoma was obtained by pathological assessment. Gallbladder carcinosarcoma has a poor prognosis. Since it is rare, no established chemotherapy or radiation protocols exist. Further studies about case series are needed to establish better therapeutic protocols. Gallbladder carcinosarcoma is a rare cancer with a rapid progression making therapeutic decisions difficult. All these factors contribute to the poor prognosis of this cancer.