Purpose: Primary radiocephalic arteriovenous fistulas (RCAVFs) have classically been used for the initiation of dialysis. If a suitable forearm cephalic vein can be demonstrated, it is used to construct such a fistula. However, we have noted a tendency for RCAVF in patients with a history of diabetes mellitus (type I and type II) to remain patent but not mature to the point of cannulation. Therefore, the present study was undertaken. Methods: Fifty-eight consecutive patients with diabetes who required initial access for hemodialysis at an urban medical center and tertiary Veterans Medical Center underwent creation of an RCAVF (n = 10), brachiocephalic arteriovenous fistula (BCAVF; n = 22), or transposed basilic vein arteriovenous fistula (TBAVF; n = 26). The vein used was determined by physical examination with tourniquet compression. If neither forearm or upper-arm cephalic veins were 2 mm in diameter, a TBAVF was created after venography. Patency was determined by Kaplan-Meier estimate; differences between groups were assessed by Fisher's exact test. Results: The 70% rate of nonmaturation of RCAVFs was significantly greater than the 27% rate for BCAVFs and 0% for TBAVFs (p < 0.05). The 33% cumulative primary patency rate at 18 months for RCAVFs was significantly less than 78% for BCAVFs and 79% for TBAVFs (p < 0.001). Within and between groups, there were no significant differences in age, gender, aspirin use, history of congestive heart failure, erythropoietin use, hematocrit level, history of peripheral vascular disease, or mortality rate. Conclusions: In patients with renal failure and a history of diabetes, both primary BCAVFs and TBAVFs demonstrate significantly greater maturation and increased primary cumulative patency rates compared with RCAVFs; therefore, these autogenous conduits are considered to be optimal in this group of patients. Whether the discrepancy in lower-arm vein maturation is a result of a lack of compensatory increase in radial arterial flow or an intrinsic defect in the lower-arm cephalic vein is currently under investigation.