To focus on psychological well-being in the Lifestyle Heart Trial (LHT), an intensive lifestyle intervention including diet, exercise, stress management, and group support that previously demonstrated maintenance of comprehensive lifestyle changes and reversal of coronary artery stenosis at 1 and 5 years. The LHT was a randomized controlled trial using an invitational design. The authors compared psychological distress, anger, hostility, and perceived social support by group (intervention group, n = 28; control group, n = 20) and time (baseline, 1 year, 5 years) and examined the relationships of lifestyle changes to cardiac variables. Reductions in psychological distress and hostility in the experimental group (compared with controls) were observed after 1 year (p < .05). By 5 years, improvements in hostility tended to be maintained relative to the control group, but reductions in psychological distress were reported only by experimental patients with very high 5-year program adherence. Improvements in diet were related to weight reduction and decreases in percent diameter stenosis, and improvements in stress management were related to decreases in percent diameter stenosis at both follow-ups (all p < .05). These findings illustrate the importance of targeting multiple health behaviors in secondary prevention of coronary heart disease.