Mental stress seems clearly and inextricably linked to the development and maintenance of high blood pressure. Blood pressure evaluated during ambulation, work, or mental stress instead of at rest or in the physician's office consistently improves the ability to predict the target-organ damage often associated with all forms of hypertension. An improved understanding of the relationship between emotional arousal and high blood pressure has accelerated knowledge surrounding the stress-related entities of white-coat hypertension, borderline or mild hypertension, circadian blood pressure changes, labile hypertension, and ambulatory or work-related hypertension. Further development and refinement of diagnostic testing devices such as ambulatory blood pressure monitors and standardized mental stress testing protocols with simultaneous blood pressure determination should improve the evaluation of the diagnostic accuracy, therapeutic efficacy, and prognostic significance associated with stress-related blood pressure elevations. These advances may be especially important because most of the morbidity and mortality associated with hypertension is seen in those with only mild to moderate elevations in blood pressure. Pharmacologic intervention directed at stress-related hypertensive entities may be helpful but remains controversial. Certainly, if instituted, drug therapy should be directed toward preservation of the target organs. Therapeutic intervention through nonpharmacologic modalities appears to be the logical treatment of choice for these hypertensive subgroups. Combined hygienic interventions may be especially powerful. Combinations of lifestyle treatment modalities optimizing nutrition, exercise, weight control, and stress management should obviate the need for medications in many cases of stress-related hypertension. Improved recognition and clinical evaluation of the relationship between environmental stress and hypertension will assist the primary care physician in the management of the blood pressure variations associated with daily life.