['Elevated YKL-40 concentrations have been observed in both coronary heart disease (CHD) and diabetes. Thus, YKL-40 may play a role in pathogenesis of CHD in patients with diabetes. We evaluated whether plasma YKL-40 concentration can predict all-cause and cardiovascular mortality in individuals with type 2 diabetes.', 'This is a prospective, observational study.', 'A total of 628 subjects with type 2 diabetes were recruited between July 1996 and June 2003.', 'Plasma YKL-40 concentrations were measured via enzyme-linked immunosorbent assay (ELISA). The cohort was followed up until 31 December 2008, when vital status and causes of death were obtained. Survival analysis and concordance statistics were performed. All-cause and cardiovascular mortalities were documented.', 'There were 153 (24·36%) mortalities, including 48 participants (7·64%) who died from cardiovascular diseases (CVDs). Participants with higher plasma YKL-40 (defined with a level above the median of 87·5 μg/l) had an increased risk of mortality. After adjusting for confounding variables, the hazard ratios (HR) for all-cause and cardiovascular mortality in participants with higher plasma YKL-40 were 1·97 (95% CI, 1·31-2·95, P < 0·01) and 2·45 (95% CI, 1·11-5·37, P < 0·05). The results remained similar after adjustment for age. Concordance statistics revealed that plasma YKL-40 concentration significantly increases the predictive power for both all-cause and cardiovascular mortality in different models.'] Does plasma YKL-40 predict 10-year cardiovascular and all-cause mortality in individuals with type 2 diabetes?