Recently, local administration bureaus have established a number of dental clinics and centers for the physically or mentally challenged (PMC) in collaboration with local dental associations. The aim of this study was to investigate dental treatment and general supportive care for the PMC in dental clinics in Tokyo. A dental clinic for the PMC located in northwestern Tokyo in a district with a population of about 680,000 was selected for the study. The variables studied based on dental records included total number of patients, type of disability, medical history, systemic condition, age, treatment regimen and type of general supportive care. The largest group of new patients was under 9 years of age. The highest total number of patients visiting the clinic belonged to the 60-69-year-olds group and the 70-79-year-olds group. We also investigated type of disability in patients treated under intravenous sedation at time of dental treatment. The most common condition was dementia resulting from Alzheimer's disease (42.74%), autism, cerebral palsy or mental retardation, in descending order. The percentage of patients referred from other medical institutions was 17.4%, including those from private dental clinics and Dental University Hospitals. Type of disability in patients transferred from other medical institutions included developmental disorders (28.2%), senile defects (26.9%), chronic and psychiatric diseases (44.9%). The number of patients who located and visited the clinic by themselves greatly exceeded the number transferred by request. This suggests that a permanent system should be put in place offering public specialized dental clinics where the PMC many obtain treatment.