This study investigated the relationship between serum selenium (Se) and glutathione peroxidase (GPx) levels and the presence of coronary artery disease (CAD) among Iranian patients. Three groups were compared: patients undergoing angiography with angiographically defined CAD, individuals with a normal angiogram, and apparently healthy controls with no evidence of overt CAD. Anthropometric measurements, blood pressure, fasting blood glucose and lipid profiles, serum Se and GPx measurements, and angiographic assessment were carried out using standard protocols. Mean serum Se concentrations were not significantly different between patients with and without CAD and the control group. The mean value of serum GPx in the control group was significantly higher than in patients with or without CAD. Selenium status did not differentiate between patients with and without CAD, which may be related to the fact that angiography is not a very sensitive index of global atherosclerosis, and it is possible that patients who were CAD negative by angiogram still have significant disease. It may also be that Se is not a good marker of CAD.