Patients with Wiskott-Aldrich syndrome, a severe inherited immunodeficiency disorder, have a markedly increased risk of developing non-Hodgkin's lymphoma compared with the general population. These are uniformly diffuse aggressive B-cell neoplasms that resemble those seen in AIDS and the posttransplantation setting and also may be associated with Epstein-Barr virus. We report what to our knowledge is the first case of follicular lymphoma in a 14-year-old child with Wiskott-Aldrich syndrome. The neoplasm was composed predominantly of large cells with immunoblastic features, and it possessed light chain-restricted surface immunoglobulin, clonal immunoglobulin gene rearrangements, and a t(14;18). The tumor lacked Epstein-Barr virus sequences by in situ hybridization and Southern blot terminal repeat analysis. Interestingly, however, the tumor contained c-myc gene rearrangement.