Posttransplant lymphoproliferative disorders (PTLDs) are almost always of B-cell derivation and have a strong association with Epstein-Barr virus (EBV). Only rare cases of CD30 (Ki-1)-positive anaplastic large cell (ALC) lymphomas in transplant recipients have been described. EBV has been studied in few of these cases. Pleural effusion is an uncommon clinical manifestation of both PTLDs and CD30-positive ALC lymphoma. A 60-year-old, male renal transplant recipient presented with fever and pleural effusion. Cytologic examination of the effusion revealed a large cell lymphoma. Immunocytologic studies disclosed a T-cell phenotype. Subsequently a cutaneous lesion and an accessory spleen were observed, and cervical lymphadenopathies developed. Fine needle aspiration of lymph nodes confirmed the presence of lymphoma. Histologic and immunohistochemical studies of the lymph nodes, skin and accessory spleen revealed the presence of CD30-positive, T-cell, ALC lymphoma. No EBV DNA was detected by polymerase chain reaction analysis. Despite chemotherapy, the patient died seven months after the initial cytologic diagnosis of lymphoma. CD30-positive ALC lymphomas are an uncommon variant of PTLDs that should be considered in the differential diagnosis of neoplastic disorders arising in immunosuppressed patients. Cytology and immunocytochemistry are useful diagnostic procedures for their early detection.