Many studies have reported that hypoalbuminemia could be associated with organ failure after liver transplantation. However, most of them focused on serum albumin levels measured at specific time points and not on the trend of serum albumin change. We investigated whether a cumulative postoperative change in serum albumin level up to postoperative day (POD) 5 is related to organ failure in patients who underwent living-donor liver transplantation (LDLT). Data of adult recipients who underwent LDLT between January 2016 and December 2020 at a single tertiary hospital were reviewed (n = 399). After screening, three patients were excluded because of insufficient data. A cumulative change in serum albumin level was demonstrated using the area under the threshold (AUT, threshold = 3.0 g/dL) of the serum albumin curve up to POD 5. Based on the AUT, the patients were divided into a high-decrease group (n = 156) and a low-decrease group (n = 240). All analyses were conducted using 1:1 propensity score matching. The primary endpoint was the Sequential Organ Failure Assessment (SOFA) score on POD 5. The secondary endpoints were postoperative hospital stay and postoperative 90-day mortality. A total of 162 patients were included. The SOFA score on POD 5 was significantly higher in the High-decrease group compared with the Low-decrease group (5.2 ± 2.6 vs. 4.1 ± 2.3; mean difference: 1.1, 95% CI: 0.3 to 1.8; P = 0.005). However, the length of postoperative hospital stay (P = 0.661) and 90-day mortality (P = 0.497) did not differ between the groups. In conclusion, a cumulative postoperative change in serum albumin level up to POD 5 could help predict postoperative organ failure on POD 5 in patients who underwent LDLT.