The aim of this case-control study was to compare the dental health of a group of long-term survivors of childhood cancer with that of age- and gender-matched healthy controls. All children who had been progress- and/or disease-free for at least 5 years were selected. Caries indices for permanent dentition (DMF/T) and primary dentition (dmf/t) were calculated. Past data were collected from medical and dental records and read separately by one of the authors. The mean age of the subjects at the initial diagnosis of the disease was 4.3 +/- 0.3 yr ( range 0.5-14 yr). The mean time lapse from the cessation of the therapy to the present dental examination was 5.0 +/- 0.7 yr. The study group had significantly (p <.001) more carious lesions in their primary teeth than the control group. The mean dmf/t value was 5.8 +/- 0.6 in the long-term survivors compared to 3.4 +/- 0.2 in the controls. The difference in DMF/T value of those children was statistically insignificant (p >.05) compared to healthy subjects (2.1 +/- 0.6 and 1.6 +/- 0.2, respectively). There was a significant positive correlation between the presence of head and neck radiotherapy (r = 0.427, p < .05), the number of months the child had been on chemotherapy (r = 0.413, p < .01), the number of fluoride gel treatments (r = .361, p < .05), and dmf/t values, separately. Based on the results of this study, our Unit now considers a through semiannual dental examination for every child who will be or has been treated at Pediatric Oncology Department to be mandatory. The focus should be on caries prevention and include dietary counseling, oral hygiene, and fluoride applications if necessary.