Objectives To investigate the relationship of serum leptin concentration with the lipids and body mass index (BMI) in patients with chronic congestive heart failure(CHF). Methods The serum concentration of leptin in 39 patients with CHF (14 in cardiac function class Ⅱ , 21 in class Ⅲ , 4 in class Ⅳ , NYHA) and in 46 patients with cardiac function class Ⅰ (NYHA) were assessed by radioimmunoassay. Results The serum concentration of leptin were 9.018±4.519μg/l in CHF group (cardiac function class Ⅱ 11.492±5.649 μg/l, class Ⅲ 7.763±3.321 μg/l, class Ⅳ 6.100±2.657 μg/l);11.674±6.911 μg/l in class Ⅰ group. The serum concentrations of leptin were significantly lower in CHF group, as compared with class Ⅰ group (P＜0.05). Moreover, the decrease of serum leptin concentration was significantly correlated with the decreased serum concentrations of total cholesterol, triglyceride, body mass index and left ventricular ejection fraction in CHF group, respectively (P＜0.05). Conclusions The significance of the decrease in serum leptin in CHF patients needs further study.