Objectives: The goal of this study was to provide a systematic review and analysis of observational studies on percutaneous left atrial appendage (LAA) occlusion for stroke prophylaxis in nonvalvular atrial fibrillation (NVAF). Background: A recent randomized controlled trial in patients with NVAF suggested noninferiority of percutaneous LAA occlusion versus medical management for stroke prevention. However, the use of percutaneous devices remains controversial because of limited literature on their efficacy and safety. We performed a systematic analytical review of existing observational studies to assess the rate of neurological events for patients treated with occlusion devices. Methods: A comprehensive search of the Medline, Scopus, and Web of Science databases from inception through August 1, 2013, was conducted using pre-defined criteria. We included studies reporting implantation in at least 10 patients and a follow-up of 6 months or more. Results: In 17 eligible studies, a total of 1,052 devices were implanted in 1,107 patients with 1,586.4 person-years (PY) of follow-up. The adjusted incidence rate of stroke was 0.7/100 PY (95% confidence interval [CI]: 0.3 to 1.1/100 PY), of transient ischemic attacks was 0.5/100 PY (95% CI: 0.1 to 1.8/100 PY), and of combined neurological events (strokes or transient ischemic attacks) was 1.1/100 PY (95% CI: 0.6 to 1.6/100 PY). Access site vascular complications and pericardial effusion were the most commonly observed procedural complications at a rate of 8.6% (95% CI: 6.3% to 11.7%) and 4.3% (95% CI: 3.1% to 5.9%), respectively. Conclusions: Our systematic review suggested comparable efficacy of LAA occlusion devices compared with historical controls treated with adjusted-dose warfarin and other anticoagulation strategies for prevention of stroke in patients with NVAF. © 2014 by the American College of Cardiology Foundation.