Polymorphisms of some genes of the renin-angiotensin system (RAS), such as angiotensinogen (AGT; M235T), angiotensin II type 2 receptor (AT2; C3123A), and angiotensin-converting enzyme (ACE; insertion/deletion (I/D)) are involved in the development and progression of coronary artery disease (CAD) in diabetic individuals. In the present study, we aimed to determine whether three polymorphisms, AGT-M235T, AT2-C3123A, and ACE I/D are associated with CAD in Saudi patients with type two diabetes mellitus (T2DM). In 266 patients with CAD (169 patients with T2DM and 97 without T2DM), restriction fragment length polymorphism analysis was used to detect polymorphisms in the three RAS genes. Within the CAD+ T2DM group, for the ACE gene (I/D), homozygous DD was found in 65.68%, 25.44% carried the heterozygous ID, and 8.88% carried the homozygous II. Within the CAD-T2DM group, DD was found in 55.67%, 26.8% carried the ID, and 17.53% carried the II. The odds ratio (OR) of the ACE ID+ DD vs. II was 2.18, with a 95% confidence interval (CI) of 1.04-4.60, and P= 0.04. Thus, we found an association between the ACE DD polymorphism and CAD in Saudi patients with T2DM, but not between the AT2 C3123A and AGT M235T polymorphisms and CAD.