Fifty-six primigravid women at 28-32 weeks gestation were studied prospectively to assess the roll over test (ROT) as a predictor of gestational hypertension in African women. Blood pressures were measured continuously in the supine and left lateral positions using an automated accutor machine. ROT was positive in only two women (3.6%). These two women later developed gestational hypertension but so did 18 others who had negative ROT. Measures that may be useful in increasing the predictive value of the ROT in these women are suggested.