Changes in physician practice for the prevention of cardiovascular disease. To determine recent changes in physicians' practices for cardiovascular disease risk reduction, a randomly selected sample of practicing primary care physicians in the upper Midwest was interviewed by telephone in 1987 and again in 1989 (response rates, greater than 90%; N = 241). The reported mean cutoff levels for labeling a total serum cholesterol level as abnormal dropped from 5.84 to 5.43 mmol/L (226 to 210 mg/dL) and for initiating medication, from 7.34 to 6.54 mmol/L (284 to 253 mg/dL). The proportion of physicians using diuretics as preferred step 1 antihypertensive agents dropped from 60% to 32%. Preferences became evenly divided among diuretics, angiotensin-converting enzyme inhibitors, and beta-blockers. Advice about physical exercise changed little, but consensus among practicing physicians was high. Substantial improvements were found in smoking cessation activities. Practicing physicians are proving to be responsive to new scientific evidence and education in the prevention of cardiovascular disease. 