Objective To investigate the correlation of plasma cartilage oligomeric matrix protein (COMP) with vascular calcification and cardiovascular events in hemodialysis patients. Methods Plasma COMP levels in hemodialysis patients and normal controls were determined and analyzed. Fifty-four hemodialysis patients were divided into two groups based on plasma COMP level, and they were followed up for 20 months. Vascular calcification of thoracic aorta was evaluated by chest X-ray examination at the beginning and after 20 months. Cardiovascular events were analyzed at the end of the follow-up period. Results At the beginning of the follow-up period, vascular calcification was detected in 20/31 and 21/23 patients in the low COMP group and the high COMP group, respectively (64.5% vs. 91.3%, p=0.023). During the follow-up period, cardiovascular events were found in 3/29 and 9/22 patients in the low COMP group and the high COMP group, respectively (10.4% vs. 40.9%, p=0.011). Regression analysis showed that higher plasma COMP level was one of risk factors for cardiovascular events in maintenance hemodialysis patients. Conclusion Elevated plasma COMP level may be a risk factor for vascular calcification and cardiovascular events in hemodialysis patients.