Objectives. Congestive heart failure (CHF) has been associated with elevated biomarker levels reflecting chronic low-grade inflammation. YKL-40 is a biomarker with increasing levels in patients with cardiovascular disease (CVD) of increasing severity. Furthermore, YKL-40 is associated with all-cause and cardiovascular mortality. We investigated plasma YKL-40 levels in patients with CHF and evaluated the possible predictive value with respect to overall mortality and recurrent cardiovascular outcomes. Design. Plasma YKL-40 was measured in 194 CHF patients and in 117 age-matched individuals without CVD. Results. Median YKL-40 levels were approximately 77% higher in patients with CHF (106 (IQR, 66-184) ng/ml vs. 60 (IQR, 42-97) ng/ml, p <0.0001). We found a trend towards an association of YKL-40 levels with urinary albumin/creatinine ratio (UACR) (beta = 0.12, p = 0.08). YKL-40 levels were not predictive of overall mortality (p = 0.59), major cardiovascular events (p = 0.23) or events of incompensation (p = 0.56). Conclusions. Plasma YKL-40 levels are elevated in patients with CHF but show no association with other clinical or paraclinical variables. YKL-40 levels were not predictive of overall mortality or incident cardiovascular events. Most likely, elevated YKL-40 levels in CHF patients are explained by the presence of concomitant diseases but a role of YKL-40 in low-grade inflammation is not excluded