The Baltimore Church High Blood Pressure Program (CHBPP) offers a behaviorally oriented weight control program consisting of eight weekly 2-h diet counseling/exercise sessions. Pre- and post-program weight and blood pressure measurements were analyzed for 184 black and 3 white women aged 18-81 years (mean 51) who participated in the program in 1984-1986: 88 were taking antihypertensive medication (Rx) and 99 were not (no Rx). Mean weight loss was 6 lb in both groups: -18 to +7 lb in the Rx group and -31 to +3 lb in the no Rx group. The mean systolic/diastolic blood pressure (SBP/DBP) decrease was 10/6 mmHg in the Rx group and 5/3 mmHg in the no Rx group (P < 0.001 for all pre/post comparisons). Final SBP was < 140 mmHg for 74% of participants, versus 52% initially. Final DBP was < 90 mmHg in 92% versus 65% initially. Supporting the inference that BP decreases among weight control program participants reflect program effects, percent changes in SBP and DBP (week 2 to week 8) were significantly correlated with percent change in weight (rs = 0.23-0.36; P < 0.05). Comparison data for 25 women from the CHBPP population showed a mean SBP/DBP increase of 8/2 mmHg over an 8-week interval. Based on follow up measurements 6 months after the end of the 8-week program for 74 of the 187 women, weight lost during the 8-week program was maintained or exceeded by 65%. Net weight change at 8 months from baseline for women in the follow up subsample ranged from -28 to +4 lb; mean (SD) -6 (7) lb. Weight loss and related dietary or behavioral changes resulting from participation in a weight control program can enhance blood pressure control among black women.