Background: Adiponectin is an adipokine with anti-inflammatory, anti-atherogenic properties and related to metabolic syndrome (MetS). Plasma adiponectin concentration is inversely related with outcomes of patients (pts) with chronic heart failure (CHF). The relationship between adiponectin and metabolic syndrome in CHF pts was not determined. Hypothesis: We hypothesized that metabolic syndrome would affect plasma adiponectin level in CHF pts. Methods: We investigated 128 CHF pts (80 males, 61.8 짹 11.9 years old, 69 ischemic origin) and age, sex, body mass index (BMI)-matched 77 healthy controls. MetS was defined as three or more of the five MetS risk factors according to modified NCEP ATP-III definition. Results: Mean adiponectin level in CHF pts was significantly higher than that of healthy controls (13.75 짹 10.13 vs 7.42 짹 3.22 ���/mL, p < 0.01). Adiponectin was positively associated with high density lipoprotein (r = 0.359, p < 0.01), and negatively associated with BMI (r = -0.352, p < 0.01), fasting glucose (r = -0.185, p < 0.05), triglyceride (r = -0.360, p < 0.01), apo B lipoprotein (r = -0.265, p < 0.05) and apo B to apo A1 ratio (r = -0.273, p < 0.021) in CHF pts. Adiponectin level was significantly lower in CHF pts with MetS than those without MetS (9.68 짹 6.97 vs 15.80 짹 10.86 ���/mL, p < 0.01). Adiponectin level was significantly decreased with higher MetS risk factors (17.08 짹 12.71 ���/mL, 14.08 짹 9.80 ���/mL, 11.26 짹 7.63 ���/mL, 6.29 짹 3.20 ���/mL vs 4.76 짹 1.78 ���/mL, respectively as 1 to 5 Mets score, p for trend < 0.001). Conclusion: Our results provide information regarding the relationships among MetS, adiponectin, and CHF.