As both essential hypertension and hypertension associated with pregnancy (pre-eclampsia) have been determined to have strong genetic components, considerable recent research has focused on identifying genes that may predispose to the development of these disorders. Recent advances in molecular genetics and the work of the Human Genome Project have facilitated the identification of genes that may be linked to these hypertensive disorders. Although molecular genetic studies performed in humans and animals can be used to link genes or mutations in genes to hypertension (once identified), studies are needed to assess their biochemical and physiologic importance. In this review, we discuss the ever-increasing importance and use of transgenic and gene-targeted mice in modeling the genetic basis of hypertensive disorders.