BACKGROUND: A native AV-fistula (AVF) for access in hemodialysis (HD) is preferable. Stenosis, a major hurdle, is associated with older age and diabetes mellitus. PURPOSE: This case-control study aimed to clarify if any medical and/or laboratory factors, that can be altered, could be associated to AVF stenosis. METHODS: 33 patients with a patent AVF without need of intervention during a two year period (Controls) were matched by diagnosis and age with 33 patients (Cases), that had at least one radiological invasive examination/intervention due to suspected AVF malfunction (case-control mode 2:1). RESULTS: Cases had higher weekly doses of Erythropoietin-Stimulating Agent (ESA) than Controls both before intervention (mean 8312 +/- 7119 U/w versus 4348 +/- 3790, p = 0.005) and after the intervention (7656 +/- 6795, versus 4477 +/- 3895, p = 0.018). Before intervention serum phosphate was higher in Cases while there was no significant difference in blood hemoglobin, weekly standard Kt/V, parathyroid hormone, calcium, albumin, C-reactive protein, smoking habits, BMI or other medication. CONCLUSION: Higher doses of ESA were administered in patients with AVF stenosis. Since ESA may cause local hypertrophic effects on the vascular endothelium, we should prescribe lower doses of ESA in patients at risk. Further studies should clarify such connection.