OBJECTIVE: Fenestrated endografts are customized, patient-specific endovascular devices with potential to reduce morbidity and mortality of complex aortic aneurysm repair. With approval from the U.S. Food and Drug Administration, our center began performing fenestrated endovascular aneurysm repair through a physician-sponsored investigational device exemption (IDE #G130210), using both physician-modified endografts (PMEGs) and company-manufactured devices (CMDs). Because these techniques are associated with specific advantages and disadvantages, we sought to investigate differences in outcomes between PMEG and CMD cases. METHODS: A single-institution retrospective review of all fenestrated endovascular aneurysm repairs was performed. The cohort was analyzed by device type (PMEG or CMD) after matching of cases on the basis of (1) number of target vessels intended for treatment, (2) extent of aneurysm, (3) aneurysm diameter, (4) device configuration, and (5) date of operation. Outcomes of ruptures, common iliac artery aneurysms, and aortic arch aneurysms were excluded. Demographics, operative details, perioperative complications, length of stay, and reinterventions were compared. For patients with >1 year of follow-up time, survival, type I or type III endoleak rate, target artery patency, and reintervention rate were estimated using the Kaplan-Meier method. RESULTS: Between November 30, 2010, and July 30, 2016, 82 patients were identified and matched. The cohort included 41 PMEG and 41 CMD patients who underwent repair of 38 juxtarenal (PMEG, 17; CMD, 21; P = .38), 14 pararenal (PMEG, 6; CMD, 8; P = .56), and 30 thoracoabdominal type I to type IV (PMEG, 18; CMD, 12; P = .17) aneurysms. There were significant differences in presentation requiring urgent aneurysm repair (PMEG, 9; CMD, 0; P = .002), total fluoroscopy time (PMEG, 76 minutes; CMD, 61 minutes; P = .02), volume of contrast material used (PMEG, 88 mL; CMD, 70 mL; P = .02), in-operating room to out-of-operating room time (PMEG, 391 minutes; CMD, 319 minutes; P = .001), incision to surgery end time (PMEG, 276 minutes; CMD, 224 minutes; P = .002), and 1-year reintervention rate (PMEG, 37%; CMD, 13%; log-rank P = .04). No differences in perioperative complications, overall length of stay, type I or type III endoleak, or survival were observed between PMEG and CMD. For the entire cohort including both PMEG and CMD, the overall rate of any 30-day postoperative complication was 39%, and the Kaplan-Meier estimate of survival at 1 year was 86%. CONCLUSIONS: In this single-institution experience of fenestrated endovascular aneurysm repair, the primary differences between PMEG and CMD related only to operative metrics and the need for postoperative reinterventions. No statistically significant advantage was found for one approach over the other; we therefore cannot conclude that one approach is better than the other. Both remain viable options that may compare favorably with open repair of complex aortic aneurysms. Further studies are necessary to determine whether this relative equivalence represents a type II error or lack of long-term durability data or whether true equivalence between PMEG and CMD approaches exists.