More than 26% of Whites studied in two rural communities were found to be hypertensive during the 1979 Coronary Risk Factor Study (CORIS). At re-study during registration at the commencement of the hypertension intervention phase, hypertension could be confirmed in 72%. The mean blood pressures had decreased, and the percentages on treatment or with control of hypertension had improved by 43% and 136% respectively, indicating that screening for, and awareness of, hypertension had beneficial results. During the first 8 months of the hypertension intervention phase, 451 hypertensives were registered in the high-intensity intervention (HII) town, and 166 in the low-intensity intervention (LII) town. In both towns decreases in mean blood pressure and increases in treatment and control percentages could be demonstrated. In the HII town 80% of hypertensives were on treatment and 83% were controlled 4 - 8 months after registration, the most impressive results being achieved in the group which began treatment as a result of the intervention. A group with mild hypertension which was treated by non-pharmacological means only also improved, 66% eventually being controlled. The hypertension programme was three times more successful in the HII town, where the results suggest that hypertension in a community can be effectively controlled in the short term, using for the most part locally available health personnel and facilities.