The consensus that portal venous pressure modulation, including splenectomy (Spx), prevents portal hypertension-related complications after living-donor liver transplantation (LDLT) has been established. However, little evidence about the risk factors for graft loss after simultaneous Spx during LDLT is available. This study aimed to identify the independent predictors of graft loss after simultaneous Spx during LDLT. Data of 655 recipients who underwent LDLT between 1997 and 2021 were collected and separated into the simultaneous Spx group (n = 461) and no-Spx group (n = 194). The simultaneous Spx group had significantly lower serum total bilirubin levels, drained ascites volumes, and prothrombin time-international normalized ratios on postoperative day 14 than the no-Spx group ( P < 0.001 for each). Incidences of small-for-size graft syndrome ( P < 0.001), acute cellular rejection ( P = 0.002), and sepsis ( P = 0.007) were significantly lower in the Spx group. Graft survival of the Spx group was significantly better than that of the no-Spx group ( P < 0.001; hazard ratio [HR], 1.788; 95% confidence interval, 1.214-2.431). A multivariate analysis revealed that 3 variables, platelet count ≤4.0 × 10 4 /mm 3 ( P = 0.029; HR, 2.873), donor age ≥60 y old ( P = 0.013; HR, 6.693), and portal venous pressure at closure ≥20 mm Hg ( P = 0.010; HR, 3.891), were independent predictors of graft loss within 6 mo after simultaneous Spx during LDLT. Spx is a safe inflow modulation procedure with a positive impact on both postoperative complications and prognosis for most patients. However, patients with the 3 aforementioned independent factors could experience graft loss after LDLT.