Obesity is a coronary heart disease (CHD) risk factor and is prevalent in patients with CHD. The authors reviewed data in 235 consecutive patients before and after formal cardiac rehabilitation and exercise training (CRET) programs and analyzed data in 72 lean patients (body mass index [BMI] <25 kg/m(2)) vs 73 obese patients (BMI>or=30 kg/m(2)). At baseline, obese patients were significantly younger (P<.0001); had higher percentage of body fat (P<.0001) and more dyslipidemia, including higher triglycerides (TG; P<.01), lower high-density lipoprotein (HDL) cholesterol (P<.0001), and higher TG/HDL ratio (P<.0001); and had higher prevalence of metabolic syndrome (61% vs 26%; P<.01) compared with lean patients. Following CRET, obese patients had small, but statistically significant, improvements in obesity indices, including weight (P<.01), BMI (P<.01), and percentage of fat (P=.03), and had more significant improvements in peak exercise capacity (P<.001), HDL cholesterol (P<.001), C-reactive protein (P<.01), behavioral characteristics, and quality of life (P<.0001). The prevalence of metabolic syndrome fell (62% to 51%; P=.1). These results support the benefits of CRET to reduce overall risk in obese patients with CHD.