We describe here the clinical and pathologic features associated with a specific translocation, t(2;13), in alveolar rhabdomyosarcoma. Tumor specimens from 14 patients with a t(2;13)-positive alveolar rhabdomyosarcoma were studied for cytogenetic-clinicopathologic correlations. Three patients had occult primary tumors; nine patients had primary tumors of the trunk (mediastinal, pelvic, or rectal). The presence of the t(2;13) was ascertained from examination of tumor involved bone marrow in ten patients who had widespread metastatic disease at the time of diagnosis. Marrow involvement was so extensive in three cases that they were initially diagnosed as acute leukemia. Response to therapy was poor, with only five patients achieving a complete response. Twelve patients have died of their disease at a median survival time of 6 months from diagnosis and one is living with recurrent disease; only one patient survives free of disease.