Muscle wasting is common in advanced heart failure. Myostatin is an important modulator of muscle catabolism. We measured serum levels of myostatin and its propeptide in patients with chronic heart failure and analyzed their relationships with clinical parameters and prognosis. The study included 70 patients: 30 in New York Heart Association (NYHA) functional class I-II and 40 in class III-IV. Their mean ejection fraction was 32%±12%. The mean follow-up time was 17.9±1.3 months. Thirteen patients (18.6%) died. No correlation was found between myostatin and myostatin propeptide levels. Nor was the myostatin or myostatin propeptide level correlated with age, sex, left ventricular ejection fraction, symptom duration, or the level of N-terminal probrain natriuretic peptide (NT-proBNP) or tumor necrosis factor-alpha receptor type-2 (TNFα R2). Moreover, no relationship was observed between the myostatin or myostatin propeptide level and NYHA functional class or mortality, in contrast to the relationships found with NT-proBNP (P<.001 and P<.001, respectively) and TNFα R2 (P=.001 and P=.005, respectively) levels. In conclusion, there was no relationship between the myostatin or myostatin propeptide level and any parameter of disease severity or prognosis in patients with chronic heart failure.