OBJECTIVE:: To systematically review and summarize the evidence of the association between preoperative alcohol consumption and postoperative complications elaborated on complication type. BACKGROUND:: Conclusions in studies on preoperative alcohol consumption and postoperative complications have been inconsistent. METHODS:: A systematic review and meta-analysis based on a search in MEDLINE, EMBASE, CINAHL, and PsycINFO citations. Included were original studies of the association between preoperative alcohol consumption and postoperative complications occurring within 30 days of the operation. In total, 3676 studies were identified and reviewed for eligibility, and data were extracted. Forest plots and pooled relative risks (RRs), including 95% confidence intervals (CIs), were estimated for several complication types. RESULTS:: Fifty-five studies provided data for estimates. Preoperative alcohol consumption was associated with an increased risk of various postoperative complications, including general morbidity (RR = 1.56; 95% CI: 1.31-1.87), general infections (RR = 1.73; 95% CI: 1.32-2.28), wound complications (RR = 1.23; 95% CI: 1.09-1.40), pulmonary complications (RR = 1.80; 95% CI: 1.30-2.49), prolonged stay at the hospital (RR = 1.24; 95% CI: 1.18-1.31), and admission to intensive care unit (RR = 1.29; 95% CI: 1.03-1.61). Clearly defined high alcohol consumption was associated with increased risk of postoperative mortality (RR = 2.68; 95% CI: 1.50-4.78). Low to moderate preoperative alcohol consumption and postoperative complications did not seem to be associated; however, very few studies were included in the analyses hereof. CONCLUSIONS:: Preoperative alcohol consumption was associated with an increased risk of general postoperative morbidity, general infections, wound complications, pulmonary complications, prolonged stay at the hospital, and admission to intensive care unit.