Conventional venography remains the preferred imaging method for pre-operative vein mapping prior to arteriovenous fistula (AVF) creation. Conventional venography is performed with iodinated contrast, which has known nephrotoxic properties. This is a recurring issue as many patients have chronic kidney disease stages 3 and 4, not yet requiring hemodialysis (HD). An alternative venography method utilizes CO2 as a non-nephrotoxic agent. We conducted a study to determine whether there was a difference in AVF success for patients who underwent conventional vs. CO2 venography An IRB approved, retrospective study was conducted. All patients (n=110) who underwent a single upper extremity venogram in 2013 at our institution’s Interventional Radiology department prior to AVF creation were included. This included conventional (n=66) and CO2 venograms (n=44). Medical records were reviewed to determine which patients underwent AVF creation at our institution. Lastly, HD records were reviewed to determine which patients were receiving adequate HD through their AVF. We utilized a previously established quantitative measurement tool, Kt/V <1.2, to define HD inadequacy. Differences in the groups were analyzed with chi-square testing. In the conventional group, 36/66 (54.5%) underwent AVF placement, compared to the CO2 group, 25/44 (56.8%) (p=0.81). Subsequent exclusions included n=9 for the conventional, and n=8 for the CO2 group. Exclusions included: death (n=3); no current HD requirement (n=6); loss to follow-up (n=5); transplant (n=2); and surgical technique (n=1). At the time of review, in the conventional group, 20/27 (74.1%) had functioning AVF, compared to the CO2 group 12/17 (70.6%) (p= 0.80). Of the functioning AVF, the median Kt/V was 1.48 in the conventional, and 1.52 in the CO2 group (p=0.59). The use of CO2 venography prior to AVF creation is potentially equivocal and sufficient when compared to conventional venography, in AVF success. In our experience, CO2 venography may be a suitable alternative for patients with renal insufficiency, not yet requiring HD, where prolonged preservation of renal function is desired.