Background: Pulmonary hypertension (PH) is a serious cardiovascular complication in patients with end stage renal disease (ESRD) undergoing hemodialysis (HD) via arterio-venous fistulas (AVF). Aim: The aim of this study was to assess pulmonary vascular resistance (PVR), AVF flow volume (AVF-FV) and cardiac output (CO) and to highlight the impact of their augmentation, as well as of the duration of HD, on the occurrence of PH in patients with ESRD. Methods: Our study group consisted of 51 dialyzed patients, with ESRD, without history of PH. We determined by ultrasonography the systolic pulmonary arterial pressure (PAPs), the left ventricular ejection fraction (EF), the cardiac output (CO), PVR and AVF-FV. Results: We documented PH in 27 (52.94%) patients. All had elevated PVR, higher AVF-FV and CO comparing to patients without PH. They were undergoing HD for a longer period and had lower EF than those without PH. For all patients, we documented strong correlations between PAPs and PVR (r = 0.933, P < 0.001) and the duration of HD (r = 0.702, P < 0.001), but moderate ones with AVF-FV (r = 0.583, P < 0.001) and CO (r = 0.519, P < 0.001).Conclusion: In patients with ESRD undergoing HD, PH was a common finding being associated with increased PVR, a longer duration of HD and chronic glomerulonephritis as etiology for ESRD. The majority of patients with PH had altered left ventricular systolic function, predisposing them to an increased risk to develop heart failure.