A prospective, randomized study evaluated the feasibility, safety, and efficacy of upper body circuit weight training (CWT) in 25 stable male cardiac patients entering the initial out-of-hospital phase of cardiac rehabilitation. Both groups performed 30 minutes of aerobic exercise only for 6 weeks. The aerobic exercise group (N = 13) continued this regimen for 6 more weeks, during which time the CWT group (N = 12) performed 15 minutes of aerobic exercise followed by CWT (two loops, eight upper body exercises). The only adverse response was in one CWT patient in whom restenosis developed. Peak heart rate during aerobic exercise and CWT was similar, but peak systolic blood pressure during aerobic exercise was significantly greater than during CWT. Peak rate pressure product during aerobic exercise and CWT was similar. Treadmill time increased significantly in both groups. Upper body strength (cumulative pounds lifted) increased significantly only in the CWT group. A coordinated program of CWT and aerobic exercise can be performed safely in stable cardiac patients during phase 2 cardiac rehabilitation, resulting in improved upper body strength and aerobic capacity.