This study was to investigate Melanoma-antigen gene (MAGE) expression by reverse transcription-nested polymerase chain reaction (RT-nested PCR) with the original common primers of MAGE-A1 to -A6 and analysis of correlation between its expression and the well-known clinical parameters in addition to evaluate the clinical feasibility of the common primers. Surgical tumor and corresponding nonneoplastic tissue samples from 38 patients with colorectal cancer were studied. To confirm the identities of RT-PCR products, direct sequencing was done after in vitro subcloning. No expression of MAGE was observed in the non-neoplastic colorectal mucosal tissues. Sixteen (42.1%) of 38 carcinomas expressed at least one of MAGE A-1 to -6. The expression of the MAGE genes was not related to age, sex, histological grades, the depth of invasion, metastasis to lymph nodes, vessel, neural, or perineural invasion. The identities with the corresponding mRNAs were confirmed in 6 cases for MAGE-A2 (15.8%), 6 cases for MAGE-A4 (15.8%), 2 cases for MAGE-A3 (5.3%), and one case for MAGE A-6 (2.6%). These results suggest that MAGE expressions, except those of MAGE-A2 and -A4, seem to have a limited role in the molecular pathogenesis of colon cancer. However, the common primer sets to detect of expressions for MAGE-A1 to -A6 simultaneously appear to be feasible to differentiate malignant from benign lesions in colorectal diseases.