Environmental factors such as stress, diet, and physical activity have long been recognized as playing an important role in the pathogenesis of essential hypertension. Individuals may vary in their response to these factors depending on differences in genes determining physiologic systems that mediate the response. In this article we discuss gene-environment interactions that contribute to the development of essential hypertension (environmental susceptibility to hypertension) and those that are involved in control of the disease (pharmacogenetics).