Epstein-Barr virus (EBV) induced lymphoproliferative disease is a well-known, feared complication of EBV primo-infection in children treated with immunomodulators or immunosuppressive drugs, eg after transplantation. As the incidence of inflammatory bowel disease (IBD) in young children is rising, more young EBV naive patients are treated with immunomodulatory agents. It is not yet clear whether these patients carry the same risk as transplanted patients to develop lymphoproliferative disease and if so, whether their evolution is comparable. We present the history of a young patient with Crohn's disease who developed an EBV related lymphoma shortly after the primo-infection while being treated with azathioprine. This case argues for a rigorous follow up of young IBD patients treated with immune suppressive drugs, also regarding EBV status.