The aim of the present study was to evaluate the long-term results of a systematic fissure sealing programme of the occlusal surfaces of newly erupted permanent first molars. All 15-year-olds (n=815) who had been regularly treated at seven Public Dental Service clinics in Jönköping County, Sweden, since the eruption of their permanent first molars participated in the study. Data on fissure sealing and restorative treatment were extracted from the dental records of the patients. When the patients were 15 years of age, it was found that 6% of the original 2456 sealed occlusal permanent first molars had received Class II restorations. Seventy-eight per cent of the remaining 2322 sealed occlusal surfaces were judged to be caries-free by the child's ordinary dentist. This long-term retrospective study indicates that a structured fissure sealing programme is of great benefit for oral health.