We report a rare case of composite angioimmunoblastic T-cell lymphoma (AILT) and diffuse large B-cell lymphoma occurring in a 48-year-old woman with generalized lymphadenopathy and hepatosplenomegaly. The patient initially sought care at a local hospital with a single enlarged left cervical lymph node. Histologic examination of the node was interpreted as an atypical immunoblastic proliferation. She developed generalized lymphadenopathy 10 months later and was referred to our institution for further evaluation. The recent biopsy of the cervical node showed typical features of AILT Flow cytometric immunophenotyping identified an aberrant CD4+ T-cell population that lacked surface CD3. Polymerase chain reaction analysis of the T-cell receptor gamma gene revealed a clonal rearrangement. In addition to the AILT, the lymph node showed partial involvement by a diffuse large B-cell lymphoma. The B lymphoma cells and admixed immnunoblasts and Reed-Sternberg-like B cells in the AILT were positive for Epstein-Barr virus (EBV) by in situ hybridization. Ourfindings raise the possibility that the EBV-associated large B-cell lymphoma is a secondary event in AILT via EBV infection or reactivation followed by clonal expansion of an immortalized EBV-infected B cell clone.