Apelin, a newly discovered adipocytokine, is produced by white adipose tissue and also expressed in kidney and heart. Increasing evidence suggests a role for apelin in the pathology of the cardiovascular system. It was demonstrated that apelin may contribute to the pathophysiology of human chronic heart failure. Apelin locates at the endothelium-a site of key functional importance in the kidney, and apelin has been shown to increase cardiac output. Cardiovascular disease is a major contributor to the mortality and morbidity of patients with chronic renal failure. We previously found that apelin was significantly lower in dialyzed patients with coronary artery disease and its level was predicted by cardiac function. Creation of a-v fistula might contribute to the development or worsening of chronic heart failure. The aim of this study was to assess associations between apelin, other adipocytokines, NYHA class and location of a-v fistula in hemodialyzed patients. This cross-sectional study was performed on a cohort of one hundred, clinically stable hemodialyzed patients. We investigated plasma apelin as well other adipocytokines: resistin, visfatin and von Willebrand factor (vWF)-a marker of endothelial cell injury. In patients with a-v fistula on the forearm (n = 77), apelin was significantly higher than in patients with a-v fistula on the arm (n = 23) (56.79 ± 23.56 vs. 43.12 ± 23.19 pg/ml). Patients with forearm a-v fistula had lower left ventricular internal end-diastolic dimension (LVIDd) (P < 0.05), left ventricular internal end-systolic dimension (LVISd) (P < 0.05), NYHA class (P < 0.05), hsCRP (P < 0.01), plasma vWF (P < 0.01), and plasma resistin (P < 0.05), whereas the ejection fraction was higher than in patients with arm a-v fistula (P < 0.05), as well as hemoglobin (P < 0.05), hematocrit (P < 0.01), prevalence of diabetes (n < 0.05), prevalence of coronary heart disease (P < 0.05), serum pH (P < 0.05), serum bicarbonate (P < 0.05). Apelin was related to echocardiographic parameters, presence of diabetes, coronary artery disease, chronic heart failure, NYHA class and serum lipids (total cholesterol, LDL, triglycerides), hsCRP, vWF, residual renal function, and Kt/V. In multiple logistic regression analysis, apelin was significantly associated with ejection fraction (beta value was -0.51, P = 0.007), the presence of diabetes (beta value 0.39, P = 0.049), a-v fistula arm location (beta value 0.42, P = 0.047). Multiple adjusted r (2) for variables in the equation = 0.45, F = 1.75, P = 0.04, SE of estimate = 20.85. Apelin level in dialyzed patients is predicted by cardiac function, presence of diabetes and location of a-v fistula. Apelin might be involved in the pathophysiology of cardiovascular disease in chronic renal failure. The arm location of the fistula might contribute to the development or the worsening of chronic heart failure in hemodialyzed patients.