A screening survey was conducted among factory workers, aged 15-64 years, in Birmingham, England to investigate ethnic differences in blood pressure. One-thousand and forty-nine subjects (784 men, 265 women) were screened, representing 79% of the eligible population. Mean systolic and diastolic blood pressures generally did not differ between men of black West Indian (n = 173), local white (n = 439) or Asian (n = 172) origin, when matched by 10-year age groups. Analysis of covariance using age as the covariate revealed that, overall, Asian men had significantly lower systolic but higher diastolic pressures than the other ethnic groups. The proportion of men arbitrarily defined as hypertensive (greater than or equal to 160 mmHg systolic or greater than or equal to 95 diastolic or blood pressures below this figure whilst receiving antihypertensive therapy) was 26% of West Indians, 22% of whites and 17% of Asians, but these were not significantly different when age was accounted for. Black West Indian women (n = 101) did have higher diastolic pressure than white women (n = 164), but this difference was dependent on body mass index. Overall, systolic pressures in women were not significantly different. These findings differ from those consistently reported from the United States.