Recently, a form of T-cell lymphoma associated with seropositivity for human T-lymphotrop virus type 1 (HTLV-1) antibody has been described in the adult population. The lymphoma frequently presents with massive hepatosplenomegaly, lymphadenopathy and circulating malignant cells, with a normal bone marrow. HTLV-1-associated lymphoma has been seen most frequently in adults from Japan, the Caribbean, and the southeastern United States. We report the first known case of a child with a lymphoma having the clinical and serological features of an HTLV-1-associated T-cell lymphoma.