About 10% of adults in Germany suffer from temporomandibular disorders (TMD). However, the prevalence of TMD in children and adolescents is still unknown. The aim of this population-based study of 1011 10- to 18-year-old children and adolescents from the Halle/Saale metropolitan area was to describe the prevalence of TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD, Dworkin and LeResche 1992). TMD pain during the last month was reported by 15% of the sample. In the clinical examination, pain in the masticatory muscles was found by 1-9% of the subjects, pain in the temporomandibular joint by 1-5%. Two percent of the subjects demanded treatment for their orofacial pain. The prevalence of reported joint noises during the last month was 13%. The prevalence of reciprocal clicking noises in the clinical examination was 23%, the prevalence of crepitation 3%. Limitations of jaw opening during the last month were reported by 4% of the subjects, in 3% the measurement of maximal jaw opening was <35mm. Female subjects reported TMD pain significantly more often compared to male subjects. RDC/TMD-diagnoses were found in 10% of the sample, the prevalence increased with age (from 10 to 18 years). The high prevalence of TMD symptoms and diagnoses in children and adolescents suggests that TMD have already substantial impact on public health in this age group. The typical gender differences and the age course of TMD suggest that adolescence plays a key role in the aetiology of TMD.