In kidney transplant (KT) recipients, cardiac impact of the persistence of an asymptomatic arteriovenous fistula (AVF) for hemodialysis has not been fully elucidated. Seventy-six patients (mean age: 49 years) without history of diabetes or cardiovascular disease underwent an echocardiography. Thirty-eight had a functioning AVF and were match-paired for age, gender and KT duration. Left ventricular mass index (LVMI) was significantly higher in patients with functioning AVF: 135.1 ± 30.3 vs. 112.4 ± 28 g/m2 (P = 0.001). Exposure to AVF increased the risk of developing high LVH fourfold. Search for a dose-effect of AVF flow revealed a trend towards increasing LVMI with higher flow: 142.6 ± 30 vs. 126.9 ± 23.9 g/m2 (P = 0.084) (median flow of the population as cut-off). Other significant changes were observed in left ventricular dimensions: greater end diastole- and systole diameters, both larger left and right atria, and left atrium diameter. Our study suggests that, in stable asymptomatic KT patients, functioning AVF has significant impact on cardiac mass, cardiac index and left ventricular dimensions. The effects on morbidity and mortality were to be investigated.