The surveillance, epidemiology, and end-results (SEER) data on 5-year relative survival rates (1973-1987) for the most common pediatric tumors (ages 0-14) were analyzed. The SEER data are population based, so the observed progress in survival from childhood cancer represents the real impact that development in cancer treatment had on the population followed by the registry. The greatest increase in survival rate from 1973 until 1987 has been achieved in hematopoietic tumors such as acute lymphocytic leukemia (ALL), in which survival increased from 47.6% (1973-1977) to 60.8% (1983-1987), and Burkitt's lymphoma in which survival increased from 27.6% (1973-1977) to 68.7% (1983-1987). Solid tumors showed a less steep, but steady increase in survival rates. Flattening in the survival rates since 1978-1982 has been observed for acute leukemia, astrocytoma, medulloblastoma, and osteosarcoma. Females have better survival rates for most pediatric tumors, except Hodgkin's disease. Analysis of race of childhood leukemia confirmed that black children have worse survival than white. When solid tumors were analyzed by stage at presentation, there was no indication that diagnosis in earlier stages of disease accounted for the improved survival. Observed flattening in the survival rates since 1978-1982 of leukemia and some solid tumors warrants further follow-up.