Introduction: Radiocephalic fistulas are the preferred type of arteriovenous fistula due to their advantageous location. However, radiocephalic fistula maturation has historically been inferior to brachiocephalic fistulas. Research indicates that intermittent compression may aid in forearm vein dilation. Early use of a compression device may assist radiocephalic fistula maturation. Objectives: This prospective, randomized, placebo controlled study evaluates device safety and the effect of intermittent compression on vein size of radiocephalic fistulas and brachiocephalic fistulas. Methods: This was an institutional review board–approved study. After fistula creation, a novel, intermittent pneumatic compression device (Fist Assist®) was worn 15 cm proximal to fistulas 6 h daily for 30 days. Those in the treatment group (n = 43) wore Fist Assist® (24 with brachiocephalic fistulas and 19 with radiocephalic fistulas). Clinical controls (n = 16) wore a sham device. Vein diameter was measured at 0 and 30 days by duplex measurement. Percentage increase was recorded and tested for significance. Results: After 30 days, the mean percentage increase in vein diameter in the radiocephalic fistula treatment group was significantly larger than brachiocephalic fistulas in the treatment group at all proximal locations from the anastomosis. Increases in percentage vein dilation for those in the radiocephalic fistula treatment group were significantly larger than those in the control group. All fistulas treated with Fist Assist® are still functional with no reported complications. Conclusion: Early application of the Fist Assist® device may be more effective at helping radiocephalic fistula mature as compared to brachiocephalic fistulas. Successful radiocephalic fistula maturation may decrease vascular access costs, reduce complications, and preserve upper arm veins for future use in vascular access.