In esophageal squamous cell carcinoma (ESCC), chemoradiotherapy (CRT) has a curative potential even in cases of locally advanced carcinoma. However, only about half of the patients benefit from CRT, and an accurate prediction of sensitivity to CRT is eagerly awaited. Using microarrays, we analyzed gene-expression patterns of pretreatment biopsy specimens from 33 patients with CRT alone including long-term survivors, more than 3 years (14 cases) and short-term survivors, less than 1 year (11 cases). The expression patterns of about 12,600 genes were used to identify genes correlated with survival terms. Fifty-seven genes correlating with short-term survival and 120 genes with long-term survival were identified. The genes involved in the immune response were characteristically upregulated in the long-term survivors, and an immunohistochemical staining confirmed an increased CD8-positive T cell number in the long-term survivors over that in the short-term survivors. In the short-term survivors, on the other hand, increased expression of the genes involved in drug resistance was observed. Our gene list should contribute to the elucidation of the mechanisms of CRT response and contains useful markers for predicting the prognosis of individual ESCC patients treated with CRT alone.