['Osteocalcin (OC) is a known bone metabolic marker and a regulator of glucose and fat metabolisms. Although bone and energy metabolisms are known risk factors for cardiovascular disease (CVD) in hemodialysis (HD) patients, few studies have examined the correlation between OC and CVD. The purpose of this study was to investigate the impact of serum OC levels on the emergence of new CVD events in HD patients.', 'We designed a longitudinal, observational cohort study in which the study patients were divided into low- and high-serum OC groups based on a median serum OC level of 71.5 ng/ml.', 'Cardiovascular disease events were observed in 29 of 126 patients (23.0 %). The number of cumulative CVD events in the low-serum OC group was significantly higher than that in the high-serum OC group, as evaluated by the Kaplan-Meier method (p = 0.0021, log-rank test). Multivariate Cox proportional hazards analysis demonstrated that a low level of serum OC is a significant predictor of a higher incidence of CVD events [hazard ratio, 2.925; 95 % confidence interval, 1.048-9.066; p = 0.0401] after adjustment.'] Are serum osteocalcin levels useful as a predictor of cardiovascular events in maintenance hemodialysis patients?