The purpose of the study was to prospectively evaluate the neuropsychological functioning of children and adolescents receiving a bone marrow transplant (BMT). One hundred and twenty-two children with malignant or nonmalignant disorders and no previous cranial radiation therapy received a pre-BMT neuropsychological evaluation. Surviving children received a 1 year post-BMT neuropsychological evaluation. Patients were placed in a chemotherapy only (chemo) or a chemotherapy and total body irradiation (chemo + TBI) group for statistical analysis. The data were analyzed by t-tests for paired samples. There were no statistically significant differences. Regression analysis failed to identify treatment, age and gender effects. The results suggest that global and specific areas of neuropsychological functioning 1 year post-BMT were not detrimentally affected by chemotherapy or chemotherapy with total body irradiation.