Background: Cardiac syndrome X, also referred to as microvascular angina, is characterized by exercise-induced chest pain, occurring despite a normal coronary angiogram. Several causes and mechanisms have been previously proposed to explain both chest pain and ST segment depression. In this study, we attempted to characterize the association, if any, between cardiac syndrome X and several factors, including blood total antioxidant status, C-reactive protein (CRP), and monocyte chemotactic protein-1(MCP-1) levels. Methods and Results: 36 patients who had been diagnosed as cardiac syndrome X on the basis of a positive treadmill test and a normal coronary angiogram, and 24 control patients, were enrolled in this study. We assessed total serum antioxidant status and CRP in these patients, and also measured the levels of such cytokines as, P-selectin, MCP-1, interleukin-6(IL-6), and interleukin-10(IL-10). Total serum antioxidant status were measured with RANDOX kit from RANDOX Lab using colorimetric method and the levels of cytokine were measured with P-seletin, MCP-1, IL-6, IL-10 kit from R&D Systems using the quantitative sandwich enzyme immunoassay technique. Total serum antioxidant levels were determined to be significantly lower in the cardiac syndrome X patients than in the controls. CRP and serum MCP-1 levels, however, were found to be significantly higher in the cardiac syndrome X group. The total serum antioxidant levels and serum MCP-1 levels were comparable to the levels observed in a group of chronic stable angina patients. Conclusions: We demonstrated increased systemic oxidative and enhanced inflammatory status in patients who had been diagnosed as cardiac syndrome X.