In previous reports, children with acute lymphoblastic leukemia (ALL), who presented with T-cell markers on their lymphoblasts (T-lymphoblasts), have been predominantly older boys often with a mediastinal mass. These children are thought to constitute a subgroup of childhood ALL that has the poorest prognosis. Here, we report five girls with ALL, who presented with T-lymphoblasts but without a mediastinal mass. All responded well to chemotherapy and three of five are in maintained remission 21-33 months after diagnosis. The fourth patient died while in remission of causes other than leukemia and the fifth relapsed and died of infection two years after diagnosis. These observations suggest that girls with T-lymphoblasts may not have an adverse prognosis.