Although trisomy 8 is the single most common numerical abnormality in acute myeloid leukemia (AML), relatively few cases with acute lymphoblastic leukemia (ALL) and trisomy 8 have been reported. We report the clinical and laboratory features of seven children with ALL and trisomy 8 as the sole cytogenetic abnormality and review nine similar cases from the literature. Among the children studied by the Pediatric Oncology Group (POG) with newly diagnosed ALL, only 0.3% had trisomy 8 as the sole abnormality. Four of our patients had T-cell ALL and three had early pre-B ALL. Presenting clinical features were typical for the respective immunophenotypes. Six of the seven children achieved complete remission. Our study suggest that trisomy 8 is an infrequent, recurring abnormality among children with ALL, which appears to be associated with a T-cell immunophenotype. © 1994.