MAGE genes code tumor antigens that are recognized by cytolytic T lymphocytes and have been shown to be expressed in various malignant tumors. However, there is still little information on the expression of the MAGE gene family except for reports of MAGE-1 and -3. In this study, we therefore investigated the expression of MAGE-4, -6, -8, -9, -10, -11 and -12, as well as MAGE-1, -2 and -3 in both cell lines and surgical samples of gastric carcinoma, using reverse transcriptionPCR. Of the investigated 11 cell lines, MAGE-4, -6, -8, -9, -10, -11 and -12 were detected in 8 (73%), 6 (55%), 2 (18%), 59 (44%), 6 (55%), 4 (36%), and 7 (64%), respectively. No expression of these genes was seen in any of the 54 samples of normal gastric tissue. In contrast, the tumor tissue samples were found to express MAGE-4, -6, -8, -9, -10, -11, and -12 in 18 (33%), 13 (24%), 6 (11%), 10 (19%), 5 (9%), 13 (24%), and 10 (19%), respectively. Forty-four (82%) of 54 gastric tumors expressed at least one of these genes. No significant correlation was observed between the expression of MAGE genes and any specific clinicopathological factors. These results may hopefully prove to be useful in developing strategies for tumor-specific immunotherapy of gastric carcinoma using MAGE gene products.