This study aimed to investigate the incidence of PTLD in pediatric liver transplant recipients and the risk factors for the development of PTLD. We also determined clinically useful quantitative EBV PCR parameters for aiding in the diagnosis of EBV-associated PTLD in the pediatric liver transplant recipients at our institute. We reviewed children < 18 years old who had undergone liver transplantations and quantitative analysis of whole blood EBV load at our institute from January 2006 to March 2015. A total of 142 liver transplant recipients were included, and their median age was 1.5 years. Clinically significant high-level EBV DNAemia ≥ 10 000 copies/mL at least twice was observed in 53.5% and PTLD occurred in 9.9%. Among PTLD group, graft failure and mortality rate were as high as 21.4% and 14.3%, respectively.Deceased donor, presence of high-level EBV DNAemia, and primary CMV infection following transplant were associated with an increased risk for PTLD in the multivariate analysis. The peak titer at 10 875 copies/mL could be used as a cutoff value with a sensitivity of 92.9% and a specificity of 37.9%; the rate of increase in EBV load suggested a sensitivity of 64.3% and a specificity of 70.9% at the cutoff value of 44 000 copies/mL/week. In conclusion, the incidence of PTLD following liver transplant in children was as high as 10%. PTLD is associated with significant morbidity and mortality. Close monitoring of EBV DNAemia is crucial for the early diagnosis and proper treatment of PTLD in pediatric liver transplant recipients. K E Y W O R D S Epstein-Barr virus, pediatric liver transplantation, post-transplant lymphoproliferative disorders How to cite this article: Seo E, Kim J, Oh SH, Kim KM, Kim DY, Lee J. Epstein-Barr viral load monitoring for diagnosing post-transplant lymphoproliferative disorder in pediatric liver transplant recipients. Pediatr Transplant. 2020;24:e13666.