Objective: To assess the influence of perioperative statin treatment on the risk of death, myocardial infarction, atrial fibrillation, and hospital and intensive care unit length of stay in statin-naive patients undergoing cardiac or noncardiac surgery. Data Sources: MEDLINE via PubMed, EMBASE, Biosis, and the Cochrane Central Register of Controlled Trials via Ovid. Additional studies were identified through hand searches of bibliographies, trial Web sites, and clinical experts. Randomized controlled trials reporting the effect of perioperative statins in statin-naive patients undergoing cardiac and noncardiac surgery were included. Study Selection: Two investigators independently selected eligible studies from original research published in any language studying the effects of statin use on perioperative outcomes of interest. Data Extraction: Two investigators performed independent article abstraction and quality assessment. Data Synthesis: Fifteen randomized controlled studies involving 2292 patients met the eligibility criteria.Random-effects meta-analyses of unadjusted and adjusted data were performed according to the method described by DerSimonian and Laird. Perioperative statin treatment decreased the risk of atrial fibrillation in patients undergoing cardiac surgery (relative risk [RR], 0.56; 95% CI, 0.45 to 0.69; number needed to treat [NNT], 6). In cardiac and noncardiac surgery, perioperative statin treatment reduced the risk of myocardial infarction (RR, 0.53; 95% CI, 0.38 to 0.74; NNT, 23) but not the risk of death (RR, 0.62; 95% CI, 0.34 to 1.14). Statin treatment reduced mean length of hospital stay (standardized mean difference, −0.32; 95% CI, −0.53 to −0.11) but had no effect on length of intensive care unit stay (standardized mean difference, −0.08; 95% CI, −0.25 to 0.10).Conclusions: Perioperative statin treatment in statinnaive patients reduces atrial fibrillation, myocardial infarction, and duration of hospital stay. Wider use of statins to improve cardiac outcomes in patients undergoing high-risk procedures seems warranted.