Poorly differentiated adenocarcinoma with lymphoid stroma occurred in the transverse colon of a 77 year old female. Numerous small lymphocytes and plasma cells were distributed in the tumor stroma. Non-isotopic in situ hybridization study for Epstein-Barr (EBV)-related small nuclear RNA (EBER-1) revealed positive signals in the nuclei of a few lymphocytes in the tumor stroma, while the tumor cell nuclei were not labeled. Immunostaining for latent membrane protein-1 was negative. The significance of detection of the EBV-infected lymphocytes in the colon tumor stroma is discussed.