We examined the relationship between the use of medical care and diastolic blood pressure (DBP) in 2,939 individuals residing in a rural Southern biracial community. The nonuse of medical care, defined as the absence of reported physician visits in the year preceding the survey, increased with higher levels of DBP among those not receiving antihypertensive treatment. Nearly one half of individuals with untreated DBP greater than or equal to 100 mm Hg had not seen a physician in the preceding year, whether aware of their hypertension or not. The association between nonuse of medical care and untreated diastolic hypertension could not be explained by demographic differences or differences in self-reported health. Despite the fact that all were referred for evaluation of their elevated blood pressure, only 28 per cent of moderate hypertensives (DBP greater than or equal to 100 mm Hg) visited their physician in the 3-month period following the survey. In contrast, 27 per cent of those with DBP less than or equal to 99 mm Hg visited their physician, although few were specifically referred.