Lymphoproliferative syndromes are the most common tumors in transplant recipients. More than 90% of posttransplantation lymphoproliferative syndromes (PTLS) are considered to be associated with Epstein-Barr virus, and 86% are of the B-cell line. Histopathology ranges from polymorphic-reactive to monomorphic forms. Clonality should be studied using molecular biology techniques. Clinically, a differentiation is usually made between early PTLS (occurring within 1 year after transplantation) and late PTLS, which occur as localized or disseminated nodal lymphomas. In localized forms, immunosuppression should be discontinued or decreased, and the involved area should be subsequently resected or irradiated. In disseminated cases, immunosuppression should be decreased and administration of acyclovir/ganciclovir should be considered. If this is not effective, treatment should be started with anti-CD20 monoclonal antibodies (rituximab). If no response occurs, use of chemotherapy, possibly with interferon, should be considered. Our aim was to report the incidence, clinical signs, and treatment in a series of patients undergoing lung transplantation (LTx).