BACKGROUND Early allograft dysfunction (EAD) is considered an important complication in liver transplantation. Serum brain natriuretic peptide (BNP) is a marker of cardiac dysfunction related to end-stage liver disease. We investigated the intraoperative change in the serum BNP level and its contribution to EAD after living donor liver transplantation (LDLT). MATERIAL AND METHODS The perioperative data of 104 patients who underwent LDLT were retrospectively reviewed and compared between patients with and without EAD. Serum BNPs were obtained at each phase, and potentially significant factors (P<0.1) were measured by univariate analysis. The intraoperative mean serum BNP level was compared with other predictors using the AUC, and was analyzed for its relationship with EAD by multivariate logistic regression. RESULTS A total of 31 patients (29.8%) developed EAD after LDLT. In all phases, the EAD group showed higher serum BNP levels than the non-EAD group. The serum BNP level at each phase was less accurate than the mean serum BNP level for EAD. The intraoperative mean serum BNP level showed higher predictive accuracy than the Child-Pugh-Turcotte, model for end-stage liver disease (MELD), and D-MELD (donor age × recipient MELD) scores (p<0.05 for all). After multivariate adjustment, intraoperative mean serum BNP level ≥100 pg/mL was identified as an independent risk factor for EAD, along with kidney disease and graft ischemic time. CONCLUSIONS During LDLT, the EAD group showed higher serum BNP levels than the non-EAD group. An intraoperative mean serum BNP level ≥100 pg/mL is independently associated with EAD after LDLT.