12-year old male status post heart transplant 8 years ago for idiopathic restrictive cardiomyopathy who presented with complaints of restless sleep and snoring. His immunosuppressive regimen consisted of cyclosporine and azathioprine. The patient was EBV-naive by PCR and serology at the time of transplantation, the donor EBV status was not known. On clinical evaluation, tonsillar hypertrophy was noted and an infectious mononucleosis-like disorder was suspected. Bilateral tonsillectomy was performed to rule out a post-transplant lymphoproliferative disorder. At the time of the procedure serologic testing for EBV (VCA-IgM and VCA-IgG) was negative and multiple prior EBV viral load analyses by quantitative PCR, performed bi-annually since organ transplantation, had been negative; the most recent was 2 weeks prior to the tonsillectomy.