Progressive muscle relaxation (PMR) is a broadly useful anxiety reduction technique that has been found to lower blood pressure (BP) in essential hypertension. The present investigation is the first to evaluate the feasibility and efficacy of wide-scale PMR instruction as a public health promotion strategy aimed at adolescents. Students (N = 1,400) in Grades 9 and 10 at two large Baltimore City public high schools underwent BP screening; those with BP persistently above the 85th percentile were randomly assigned to (a) 12 weeks daily PMR instruction provided in class for academic credit or (b) a control condition. The latter students had their BP measured at the same frequency as the PMR students and completed the PMR course during the following year. Approximately two thirds of eligible students entered and completed the study. Results demonstrated that treatment students (n = 51) enjoyed daily PMR, mastered the technique, and achieved reduced systolic BP at posttest relative to the untrained controls (n = 59). At follow-up 4 months later, group BP differences were not significant. Implications for use of PMR to promote cardiovascular health are discussed.