Accurate prediction of human tumor response to radiation therapy and concomitant chemoradiation would be an important tool to assist the physician in making recommendations for tumor treatment. Most of the studies that define the molecular markers for prediction of radiation response are based on the observation of gene expression using immunostaining, Northern blot, or Western blot analysis of a single or several genes. The results vary among different studies, and some results are contradictory. However, the studies agree that the change in expression of the tumor-related gene affects the radiation response. In this study, we explored a novel approach to predict the radiation response of human tumor using Atlas human cancer 1.2 cDNA array to analyze the expression profile of 1187 tumor-related genes in radiation-resistant and radiation-sensitive tissues. Sixty tumor-related genes were selected as predictors of radiation response of squamous cell carcinoma of the head and neck. Using the expression intensity of these 60 tumor-related genes, in combination with cluster analysis, we successfully predicted the radiation identity of two tumor samples.