Carcinosarcomas are rare, malignant, biphasic tumors. We report the case of a 62-year-old man with gastric carcinosarcoma, along with its clinical, macroscopic and histopathological features. Macroscopically, a specimen of deformed stomach was obtained that measured 200 mm x 150 mm x 100 mm. A 150 mm x 100 mm x 50 mm exophytic tumoral mass (Borrmann type I) was found, which involved the posterior wall from the cardia to the antrum. Histopathologically, a mixed type of malignancy was revealed: an adenocarcinoma with intestinal metaplasia, with interposed fascicles of fusiform atypical cells and numerous large, rounded and oval cells. The tumor showed positive histochemistry for cytokeratin 18, epithelial membrane antigen, carcinoembryonic antigen, chromogranin A and vimentin. Liver metastases were diagnosed 8 mo postoperatively, and the patient died 4 mo later. A review of the available literature is also presented.