Background: Postoperative infection remains a serious complication of cardiac surgery; however, no existing biomarkers can detect infection in the early perioperative period. We investigated the usefulness of presepsin, a novel biomarker, in predicting postoperative infectious complications in cardiac surgery with cardiopulmonary bypass.Methods: For patients aged > 18 years who underwent elective cardiac surgery with cardiopulmonary bypass between 2015 and 2017, data of clinical features, perioperative presepsin levels, and infectious complications were collected. We compared the perioperative presepsin levels between the infected and non-infected groups, performed a risk factor analysis for postoperative infection, and calculated the cut-off value of presepsin with postoperative infection.Results: Among the 73 included patients, 20 developed postoperative infectious complications. The presepsin levels pre-operatively and on post-operative day (POD) zero were significantly higher in the infected than in the non-infected group (145.2 vs. 93.2, 514.0 vs. 328.1 [pg mL(-1)], p < 0.05, respectively). The odds ratio (OR) for postoperative infection included pre-operative presepsin (OR; 1.22 [ confidence interval; 1.07-1.40]/10 pg mL(-1)) and presepsin on POD zero (OR; 1.31 [confidence interval; 1.05-1.64] /100 pg mL(-1)). The cut-off predictive values for postoperative infectious complications of pre-operative presepsin and on POD zero were 132 and 347 [pg mL(-1)], respectively.Conclusions: Perioperative presepsin levels could be an early predictor for postoperative infectious complications in cardiac surgery.