Weight gain leading to obesity is a frequent adverse effect of treatment with atypical antipsychotics. However, the degree of its independent contribution to the risk of coronary heart disease events in patients treated with these drugs has not been elucidated. The aim of this study is to determine whether obesity is an independent risk factor for the 10-year risk of coronary heart disease events in psychiatric patients treated with atypical antipsychotics. We used the Framingham method, which is based on age, gender, blood pressure, smoking, and plasma levels of total and high-density lipoprotein cholesterol, to estimate the 10-year risk of coronary heart disease events in patients treated with second-generation antipsychotics who were obese (N = 44; mean age 38.1 years, 54.5% men) or normal weight (N = 83; mean age 39.9 years, 47.0% men). Excluded were patients with metabolic syndrome and those taking antihypertensive, hypoglycemic, and lipid-lowering drugs. The 10-year risk of coronary artery disease events was very low and virtually identical in the obese and normal weight patients (2.3 ± 3.5 vs. 2.6 ± 4.6, P = 0.68), despite excess of 12 BMI units (P < 0.0001) and 15.7 cm waist circumference (P < 0.0001) in the obese. The risk was similar in obese and normal weight men (3.8 ± 5.9 vs. 2.8 ± 3.4, P = 0.45) and women (1.7 ± 3.7 vs. 1.5 ± 2.5, P = 0.83). The validity of the 10-year prediction for risk of coronary heart disease events in the mentally ill based on the Framingham score system requires prospective confirmation. Obesity does not appear to be an independent predictor for the 10-year risk of coronary heart disease events in patients without metabolic syndrome treated with second-generation antipsychotics.