Longitudinal variations of subjective symptoms and clinical signs of craniomandibular disorders, orofacial parafunctions, and occlusal conditions were examined in 131 Finnish adolescents. Patients were interviewed and clinically examined at the ages of 14, 15, and 18 years. Signs and symptoms of craniomandibular disorders were common, although usually mild. Reported and recorded temporomandibular clicking sounds were the most frequent findings and increased with age. They showed, however, no predictable pattern, and only a few patients consistently reported clicking sounds or had them recorded. Although the frequency of craniomandibular disorders according to Helkimo's clinical dysfunction index was high at each examination, there also was great intraindividual fluctuation longitudinally; impairment and improvement occurred almost equally often, showing no predictable pattern. Only 3% of those tested consistently had an index value of more than I. Thus, even longer follow-up studies are needed to understand natural longitudinal variations and evaluate the need and demand for treatment of craniomandibular disorder.