Plasmablastic lymphoma is a rare and aggressive lymphoma characterized by the diffuse proliferation of large neoplastic cells resembling immunoblasts with an immunophenotype of plasma cells. A 47-year-old male was referred to our hospital with gastrointestinal bleeding, and a mass 10 cm in diameter, was detected. An endoscopic biopsy was performed subsequently. Histopathological examination of the biopsy material revealed ulcer, alterations associated with ulcer, and further presented a diffuse infiltration of atypical cells with abundant cytoplasm and pleomorphic nuclei, some with crush artifacts in lamina propria. Immunohistochemically, the tumor cells were negative for cytokeratin, CD2, CD20, and PAX5; but they were positive for CD3, MUM1, CD38 and CD138. Ki67 proliferation index was as high as 95%. The case was signed out as CD3-positive plasmablastic lymphoma with clinical, histopathological and immunohisto-chemical findings. The plasmablastic lymphoma case with an aberrant CD3 expression has been presented here, which is rarely observed in stomach.