In the present study, micrometastasis in the rib marrow of 24 patients with esophageal cancer was examined using RT-PCR. RT-PCR was done using primers corresponding to cytokeratin 18 (CK18), squamous cell carcinoma antigen (SCC), and carcinoembryonic antigen (CEA). In 18 cases, CK18 was also detected in the rib marrow. Only one patient exhibited CEA amplification in the rib marrow. No cases demonstrated SCC amplification as a marker of micrometastasis in the rib marrow. The information from micrometastasis detected in the rib marrow using RT-PCR is useful in deciding whether or not adjuvant therapy is necessary after surgery. However, combined analysis using plural markers should be required since sensitivity or specificity of each marker may vary. Further follow-up of the patients is necessary to clarify the clinical impact of micrometastasis in rib marrow.