We studied the association between the outcome of antihypertensive care and three items of that care among 230 hypertensive steelworkers who were referred to 83 physicians. The first item was the decision to treat some patients but not others: 63% of the patients were prescribed antihypertensive drugs and the mean decrease in their diastolic blood pressure (DBP) was greater than that among untreated patients (12.2 ± 0.84 vs 7.8 ± 0.83 mm Hg [± SEMI, p < 0.001). The second item was the vigor of prescribed medication: Patients prescribed more vigorous treatments had lower DBP (p< 0.005). Third, patient compliance was related to achieving a goal DBP of less than 90 mm Hg (p< 0.05) and the product of prescribed vigor and compliance was highly associated with DBP response (p< 0.0001). These results stand in contrast to those of previous studies that failed to detect associations between various other items of the care process and the outcome of antihypertensive care.