Internal derangement has been suggested to be a cause of temporomandibular disorders. This study compared magnetic resonance imaging findings in 82 asymptomatic volunteers and 263 symptomatic patients. Disk displacement was observed in 33% of the asymptomatic volunteers and 84% of the symptomatic patients. The prevalence of trauma, headache, and other joint problems was more common in symptomatic patients. A history of general anesthesia and orthodontic treatment was not increased in the symptomatic population compared with asymptomatic volunteers. This study suggests that disk displacement is more common in symptomatic subjects.