Most episodes of fistula thrombosis are consequences of underlying physioanatomic abnormalities. However, some dialysis access thrombosis develops independent from any obvious anatomic cause. We aimed to clarify the role of thrombophilias in primary and secondary AVF failure. One hundred eighty nine arteriovenous fistulas in 116 adults on maintenance hemodialysis were analyzed. All subjects were evaluated for many thrombotic factors. Fistula information was obtained both from the patients' self reports, and from their medical records. Twenty-seven AVFs in 18 cases (14.3%) had pAVFF. The percentage of subjects with a BMI < 20 kg/m(2) was significantly lower than no-pAVFF group (P = 0.03). ATIII levels and albumin values were significantly lower in patients with sAVFF compared to those with no sAVFF. Other parameters were similar. There was no statistically significant difference between pAFFF versus No-pAFFF and sAFFF versus No-sAFFF groups with respect to all mutant alleles count. Routine extended analyses of all thrombophillic factors are not recommended in AVFF.