Abstract    BACKGROUND: Access to vascular system needed for hemodialysis among patients in end stage renal disease (ESRD). Cardiac performance has been affected by chronic renal failure based on several known causes during diseases process. We have compared in this study some of cardiac performance indicators before and after fistulization in diabetic and non-diabetic ESRD patients.    METHODS: Fifty ESRD patients were included in the study. Systolic pulmonary arterial pressure (PAP), cardiac output (CO) and ejection fraction (EF) were measured by echocardiography before fistulization and was repeated at least 8 months after fistulization. Data analyzed in diabetic and non-diabetic patients. RESULTS: Thirty four patients were included in analysis (28 men and 6 women). Mean time of follow up was 10.5 ± 1.3 months. The mean of PAP before and after fistulization was 25.16 mmHg and 21.3 mmHg, respectively in all individuals (P > 0.05). The mean of cardiac output before and after making fistula was 5580 ml/min and 5680 ml/min, respectively (P < 0.05). Diabetic patients showed a significant reduction in their mean of cardiac ejection fraction before and after intervention (EF1 = 66.9%, EF2 = 51.4%) comparing with non-diabetic patients (EF1 = 58.5, EF2 = 57.5) (P < 0.05). PAP changes and CO changes had not any significant difference between diabetic and non-diabetic patients. DISCUSSION: Fistulization in ESRD patients can improve cardiac performance among these patients. This change may be differing among patients based on the cause of renal failure. Diabetes mellitus may be one of the parameters that can modulate this affect. This should be test in more detailed studies.      Keywords: Fistulization, End Stage Renal Diseases, Cardiac Performance, Diabetes mellitus