A 17-yr-old girl in end-stage renal failure was due to undergo living-related pre-emptive renal transplantation when she developed acute infectious mononucleosis (AIM) from Epstein-Barr virus (EBV). In view of the risk of post-transplant lymphoproliferative disorder (PTLD) we were unsure as to the optimal delay between AIM and renal transplantation. This report describes the process used to determine maturation of the immune response to EBV using a combination of serology, immunophenotyping and molecular viral load estimation. These tests showed that EBV had not been cleared and dialysis was instituted rather than proceed directly to transplantation. After EBV viral load became undetectable in the blood, living-related donor was successfully performed 13 months after AIM. With 42-month post-transplant follow up there has been no evidence of PTLD.