Background: Adiponectin, an adipocyte-derived hormone, has been shown to prevent the progression of left ventricular hypertrophy (LVH). However, recent studies have demonstrated increased levels of adiponectin according to the severity of chronic heart failure. We therefore investigated the relationships between adiponectin, brain natriuretic peptide (BNP), and LVH in type 2 diabetic patients on hemodialysis. Methods: The study population comprised 41 type 2 diabetic patients on hemodialysis. Left ventricular mass index (LVMI) and criteria for LVH were determined on the basis of echocardiographic findings. Serum adiponectin and plasma BNP levels were assayed with a commercially available kit. Results: Serum adiponectin levels significantly correlated with BMI (r = –0.49, p < 0.01), HDL-C (r = 0.36, p < 0.05) and TG (r = –0.49, p < 0.01). In addition, serum adiponectin levels correlated significantly and positively with plasma BNP levels (r = 0.36, p < 0.05). This relationship remained significant after adjustment for age, gender, and BMI (r = 0.34, p < 0.05). Serum adiponectin levels as well as plasma BNP levels were significantly higher than in patients without LVH (p < 0.05; p < 0.01, respectively), accompanied by a positive correlation between these levels and LVMI (r = 0.42, p < 0.01; r = 0.32, p < 0.05, respectively). Conclusion: Increased levels of adiponectin were associated with elevated BNP levels and LVH in hemodialysis patients with type 2 diabetes mellitus. It is speculated that adiponectin levels may be modulated by chronic hypervolemic state in this population.