The effect of high job strain (defined as high psychological demands plus low decision latitude at work) on blood pressure was determined in 129 healthy, nonhypertensive men (n = 65) and women (n = 64). Blood pressure measures included mean screening levels obtained in a clinical environment, mean ambulatory levels from one 8-hour workday, and the change in levels from screening to mean work levels. In male workers, men with high and low job strain showed similar blood pressures at screening, but men with high job strain showed greater increases from screening to work, resulting in higher mean work blood pressure. Occupational status was unrelated to job strain or blood pressure in men. In female workers, women with high and low job strain did not differ in any measure of blood pressure; however, there were trends for higher occupational status and greater skill discretion to be associated with higher blood pressure responses at work in women.