Background. The prevalence of arteriovenous (A-V) fistula use is lower among female than male hemodialysis patients. This difference may be due, in part, to smaller vessel diameter in women. However, even when routine preoperative vascular mapping is used to select vessels with suitable diameters, fistulas are still less likely to mature in women than in men. Methods. To explore the reasons for this gender discrepancy, we evaluated the outcomes of 230 A-V fistulas placed at our institution after preoperative mapping. Vessel diameters, radiologic and surgical interventions, and fistula adequacy for dialysis were assessed. Results. Fistula adequacy for dialysis was lower in women than men (31 vs. 51%, P = 0.001). The inferior outcome of fistulas in women was observed for both forearm fistulas (18 vs. 43%, P = 0.02) and upper arm fistulas (39 vs. 60%, P = 0.04). Differences in vessel diameter did not explain the lower patency rate of fistulas among women. Among fistulas not lost due to technical failure or early thrombosis, 31% underwent one or more interventions (salvage procedures) due to failure to mature. These interventions included angioplasty, ligation of tributaries, superficialization, and surgical revision of the anastomosis. A salvage procedure was more likely in women than in men (42 vs. 23%, P = 0.04). The likelihood of fistula maturation after an intervention was similar among women and men (50 vs. 37%, P = 0.40). Salvage procedures increased the proportion of adequate fistulas to a greater degree in women than in men (relative increases of 68 and 15%, respectively). Conclusions. These data suggest that fistulas are less likely to be useable for dialysis in women than in men, despite routine preoperative mapping and frequent interventions undertaken to salvage immature fistulas.