The association between self-monitoring (regulation and control of nonverbal and expressive behavior) and blood pressure was examined in a field study of 594 municipal employees. For persons not taking antihypertensive medication, the Acting/Extraversion scale was mildly positively associated with resting blood pressure among whites in general, blue collar, clerical, and professional groups. Stronger positive correlations were obtained for attorneys and customer service representatives. These results are contrasted with slightly negative associations for blacks in general, first-level supervisors, and a group of previously studied union stewards. An interactive effect was also obtained between Acting/Extraversion and relative participation in work versus nonwork groups and activities; Acting/Extraversion and systolic pressure were inversely related for employees more active in extrawork groups but not related among other workers. Differential consequences of greater or lesser interpersonal involvement and emotional regulation in different jobs are considered.