A survey was performed from April 1975 to Oct. 1978, on the high blood pressure of workers employed at industries in Busan area in order to seek for the environmental factors on blood pressure. The number of workers surveyed in the manufacturing industries occupied 72.4 percent of the total. By the age group of all workers, 39.9 percent belonged to the 20-29 year group. For the age distribution and sex of the workers, the highest frequency was found in the 20-29 year group in both sexes and was 36.8% and 46.1% in male and female, respectively. The prevalence rate of hypertension among the workers was 15.9. The industries showing the highest prevalence rate equivalent to wholesale, retail trades, restaurants, and hotels. This survey presented a tendency of increasing prevalence rate as the age increases.