Fifty million people in the US have hypertension. The JNC-V guidelines provide treatment recommendations for hypertension. These guidelines promote initiating therapy with diuretics and beta blockers since these agents have been shown to reduce hypertension-related morbidity and mortality. OBJECTIVES: To survey primary care physicians' antihypertensive prescribing practices, their perceptions about antihypertensive medication cost and safety and the perceived impact of managed care. METHODS: A direct mail survey was sent to a national random sample of 500 office based, primary care internists, family practitioners and general practitioners. RESULTS: Seventy-two percent of physicians reported being aware of the JNC-V guidelines. Younger physicians claimed to be more aware of and more likely to follow JNC-V guidelines than older physicians. Only 25% of physicians reported initiating treatment at systolic blood pressures greater than 140 mm Hg as recommended by the JNC-V guidelines. Diuretics were selected by 36% of physicians, angiotensin-converting enzyme (ACE) inhibitors by 35%, beta blockers by 16% and calcium channel blockers (CCB's) by 7% for initial antihypertensive treatment. Up to 27% of physicians admitted not knowing the cost of specific medications. Approximately half of physicians reported that they and their patients were more concerned about medication cost and safety today than 18 months ago. A greater number of younger physicians than older physicians reported that managed care formularies infringed upon their prescribing practices. CONCLUSIONS: Antihypertensive prescribing patterns are inconsistent with JNC-V guidelines. Actual practice may deviate even more from these guidelines than reported in this survey. Also, primary care physicians perceive that managed care is increasingly affecting their prescribing practices.