Radiographic findings in temporomandibular joints (TMJ) of asymptomatic adolescents have been reported, probably because such patients are unlikely to undergo routine TMJ radiography. The purpose of this prospective study was to document radiographic findings in TMJ's of adolescents without a history of TMJ dysfunction to determine prevalence of osseous, positional and functional abnormalities. Corrected sagittal TMJ tomographs in closed and open positions from pre-orthodontic records of 498 adolescent patients aged 8 to 15 years old were studied by one observer. Positional, functional or osseous abnormalities were each found in less than 10% of TMJ's. One percent of joints demonstrated marked limited mobility. There was no significant difference between right and left sides. Our results suggest that routine radiography of TMJ's in adolescents is not a useful screening too although longitudinal studies are necessary to determine whether asymptomatic adolescent patients with radiographic abnormalities will develop signs and symptoms of TMJ dysfunction.