Soluble forms of vascular adhesion molecules, ICAM-1 and VCAM-1, accelerate atherosclerosis pathogenesis. The present study was conducted to evaluate the effect of daily supplementation of 3 g cinnamon on the plasma levels of ICAM-1 and VCAM-1 among patients with type 2 diabetes. This randomized double-blind placebo-controlled trial was performed on 44 adult patients with type 2 diabetes aged 25-70 years. The patients were randomized to two groups of intervention (n = 22) and control (n = 22), differing by daily cinnamon supplementation or placebo (3 g) for 8 weeks. Plasma levels of ICAM-1 and VCAM-1 were measured at the beginning and end of the study. After 8 weeks, 39 subjects (n = 20 in the cinnamon and n = 19 in the placebo groups) completed the trial. There was a significant reduction in the mean levels of ICAM-1 and VCAM-1 within cinnamon and placebo groups (P < 0.001). But there was no significant difference in ICAM-1 (P = 0.75) and VCAM-1 (P = 0.72) between the groups at the end of the trial. According to the results, cinnamon supplementation has no beneficial effect on the reduction of ICAM-1 and VCAM-1 levels in patients with type 2 diabetes, which have a role in the development of atherogenesis.