The etiology of coronary artery disease (CAD) is multifunctional. There is increasing evidence that dental infections could play a role in the initiation and development of CAD. In a case control double blind study, one hundred male and female (mean age 51 ± 9.4) angiographically documented CAD, compared with one hundred male and female patients (mean age 50.6 ± 9) with angiographically negative coronary artery. All the patients (cases and control) underwent dental examination for the presence and severity of periodontitis by a dentist who was oblivious the result of the angiography performed. The association between periodontal disease status and CAD was significant (P=0.011); periodontitis was apparently more frequent in CAD positive patients than in control (86% versus 61%). Adjustment of coronary risk factors (smoking, DM, hypertension and hyperlipidemia) in both cases and control groups suggests that the association between periodontitis and CAD in our study was independent of coronary risk factors. There is increasing evidence that dental infection, especially aerobic organisms which have capability of aggregation of platelets, is the most important cause. Dental infection would be an independent risk factor for CAD.