Transcatheter aortic valve implantation (TAVI) has emerged as an important treatment for patients with severe symptomatic aortic stenosis who are at high operative risk, but accurate estimates of serious adverse effects in contemporary practice are not available. To quantify the adverse effects associated with TAVI, and to evaluate whether the type of transcatheter valve and the route of valve implantation are associated with differences in adverse outcomes. PubMed to 5 May 2012. All studies that included at least 100 patients who had TAVI and reported at least 1 outcome of interest. Two reviewers abstracted the data independently. A random-effects model was used to combine data on adverse outcomes and conduct stratified analyses. A total of 49 studies enrolling 16 063 patients met the inclusion criteria. Overall 30-day and 1-year survival after TAVI were 91.9% (95% CI, 91.1% to 92.8%) and 79.2% (CI, 76.9% to 81.4%), respectively. Heart block requiring permanent pacemaker implantation was the most common adverse outcome (13.1%) and was 5 times more common with the CoreValve (Medtronic, Minneapolis, Minnesota) than the Sapien valve (Edwards Lifesciences, Irving, California) implanted using the transarterial route (25.2% vs. 5.0%, respectively). The overall rate of vascular complications was 10.4% and was highest with transarterial implantation of the Sapien valve (22.3%). Acute renal failure requiring renal replacement therapy was the third most common complication, occurring in 4.9% of patients. Rates of major vascular complications may be overestimated owing to rapidly evolving TAVI technology. The most common adverse effects associated with TAVI are heart block, vascular complications, and renal failure. The type of transcatheter valve and the route of implantation are associated with observed variations in the risks for some adverse effects. Heart and Stroke Foundation of Canada.