The field of genetic toxicology occupies a unique and somewhat paradoxical role in the area of risk assessment. It is the only field in which most of the data generated do not measure truly toxic events. That is, many of the end points measured do not clearly represent adverse effects for the cell or organism of study. The chapter presents a discussion of some of the major components of heritable genetic risk assessment from chemical exposure, including hazard identification, dose-response assessment, dosimetry, dose-response extrapolation, exposure assessment, and risk characterization.