Abstract: One major challenge facing todays cancer researchers is the development of new approaches for the identification of carcinogens and other environmental hazards. Here, we describe the potential impact of emerging technologies for measuring gene expression profiles on carcinogen identification and on the general field of radiation carcinogenesis. An example of one of these technologies is the use of DNA chips. We provide an overview the mechanism and applications of DNA chip, and the application to study on molecular mechanism of radiation carcinogenesis.