Major strides in the molecular biology of essential hypertension are currently underway. This has tended to obscure the fact that a number of inherited disorders associated with low blood pressure exist and that these diseases may have milder and underrecognized phenotypes that contribute importantly to blood pressure variation in the general population. This review highlights some of the gene products that, if abnormal, could cause hypotension in some individuals. Diseases due to abnormalities in the catecholamine enzymes are discussed in detail. It is likely that genetic abnormalities with hypotensive phenotypes will be as interesting and diverse as those that give rise to hypertensive disorders.