Objective: This study aimed to observe the effect of simvastatin on the serum monocyte chemoattractant protein-1 (MCP-1) and intracellular adhesion molecule-1 (ICAM-1) levels and to probe its protective mechanisms on macroangiopathy in diabetic rats. Methods: Twenty-four Wistar rats were randomly assigned to a normal control group (Group A, n=8), and STZ-induced diabetic group (Group B, n=8), or a simvastatin-treated diabetic group (Group C, n=8). Rats in Group C were treated with simvastatin (20 mg kg day) 1 week after the establishment of the diabetic model. Groups A and B were treated with corresponding sodium chloride. Peripheral blood glucose was tested weekly; serum MCP-1, ICAM-1, and HbA1c levels were tested at the eighth week. Results: At the second, fourth, and eighth week, peripheral blood glucose levels in Group B were similar to those of Group C, which were much higher than those of Group A. Serum MCP-1 and ICAM-1 levels in Groups B and C were higher than those of Group A (P<.01), and serum MCP-1 and ICAM-1 levels in Group C were lower than those of Group B (P<.01); HbA1c was not significantly different between Group C and Group B. Conclusion: Simvastatin has the effect of anti-inflammation, which may play some protection against the progress of atherosclerosis in diabetic rats. © 2009 Elsevier Inc. All rights reserved.