Procedural complications following transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) are usually reported as retrospective analyses. We report the first comparison of complications following SAVR or self-expanding TAVR from a prospectively randomized study of high-risk SAVR patients. Three hundred ninety-five TAVR and 402 SAVR patients were prospectively enrolled and randomized 1:1 to TAVR with a CoreValve bioprosthesis or a surgical bioprosthetic valve. The rates of major procedural and vascular complications occurring (periprocedurally (0-3 days) and early (4-30 days)) were compared for TAVR vs SAVR patients. All-cause mortality, stroke, myocardial infarction, and major infection were similar in both periods post procedure. Within 0-3 days, the major vascular complication rate was significantly higher with TAVR (P = 0.003). Life-threatening or disabling bleeding (P < 0.001), encephalopathy (P = 0.02), atrial fibrillation (P < 0.001), and acute kidney injury (P < 0.001) were significantly higher with SAVR. Non-iliofemoral TAVR approaches had a higher incidence of major or life-threatening or disabling bleeding at 0-3days (P < 0.05). Procedural complications unique to TAVR included coronary occlusion 0.5% (2) and TAVR pop outs 2.8% (11) with no valve embolizations. Pop outs were similar between iliofemoral 2.8% (9/324) and non-iliofemoral approaches 3.0% (2/66). Procedural complications unique to SAVR included aortic dissection 0.8% (3/357) and injury to other heart structures 2.0% (7/357). The procedural complication profiles of TAVR and SAVR are unique. Intraoperative deaths were seen in TAVR only. Mortality at 3 and 30 days was similar. The higher incidence of some complications likely reflects the greater invasiveness of SAVR in this aged high-risk population.