Several studies have reported a decline in intelligence and cognitive functions in survivors of childhood acute lymphoblastic leukemia (ALL). Other investigators, however, have found no intellectual impairment in these children. Fifty-one long-term survivors of ALL, having been treated according to the protocols of the BFM Study Group from 1970 to 1979, were assessed retrospectively using neurophysical methods. The results were compared with those obtained from 30 patients with other malignancies, who had received neither radiation therapy to the central nervous system (CRT) nor any methotrexate during chemotherapy. Additionally, neurological examinations and cranial computed tomography (CCT) were performed. neuropsychological examinations included verbal functions, intelligence (performance), psychomotor speed, motor skills and sensory integration. The results of verbal tests and the IQs, tested by nonspeed-related measures, were within normal limits in both groups. About one-third of all patients showed mild disturbances of psychomotor speed and motor skills. Children with leukemia had lower scores than those with solid tumors for nearly all tasks, but only tests for sensory integration revealed significant differences between former ALL patients and tumor patients. Furthermore, the following results were obtained related to different therapeutic modalities: The higher total radiation doses had been during CRT (maximum 24 GY), the more neuropsychological functions were impaired, particularly motor accuracy and sensory integration. These disturbances improved with the length of survival. Widening of subarachnoidal space was found in 33% of the CCT obtained. There was no correlation between the intellectual functions of the survivors and the CCT abnormalities. Neurological findings mainly consisted of slight fine motor disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)