Introduction: Malnutrition is a factor that defines vital prognosis in chronic heart failure. Objective: This study investigated nutritional and metabolic disorders in patients with heart failure by examining the association of severity of heart failure with inflammatory cytokines, appetite-regulating hormones, and energy metabolism. Methods: Subjects were 50 patients with heart failure. On admission, nutritional status was assessed, and biochemical blood tests were performed, including for serum tumor necrosis factor-α, interleukin-6, ghrelin, and leptin levels. Resting energy expenditure (REE) was also measured by indirect calorimetry to examine its association with severity of heart failure and levels of inflammatory cytokines and appetite-regulating hormones. Results: There were significant associations between serum brain natriuretic peptide (BNP) level and nutrition indices, indicating that nutritional status was worse when heart failure was more severe. Inflammatory cytokine levels showed significant positive correlations with BNP level. Measured REE/bodyweight was not associated with severity of heart failure, but was negatively correlated with body fat percentage and leptin levels. Conclusions: Energy metabolism was not associated with serum BNP level among patients with heart failure with New York Heart Association functional class up to III. Body fat percentage and leptin levels may be a good predictor of energy metabolism in patients with heart failure.