An epidemiological survey of blood pressure was carried out among men employed at a single factory in Ibadan, Nigeria. All available employees participated, with only four persons excluded at the time of analysis for missing data. Hypertension was uncommon (blood pressure greater than or equal to 160/95 = 8%) and little rise in mean blood pressure was observed with age. Obesity was likewise uncommon, although body mass index was related to blood pressure (r = 0.22; P less than 0.01). Contrary to reports from Western industrialised countries, education was found to have a significant positive association with blood pressure, and this finding was independent of age, body mass index, pulse, and alcohol consumption. The process of modernisation is associated with rising blood pressure in West Africa at the present time, but the absolute risk remains low.