Correct diagnosis of internal derangements of the temporomandibular joint requires both a comprehensive clinical and radiographic evaluation. Plain film tomography, transcranial radiography, arthrography and computed tomography have all been used to assess the status of the joint structures. Magnetic resonance imaging is a relatively new modality used for imaging many different organ systems. Magnetic resonance imaging of the temporomandibular joint has certain distinct advantages over previously used techniques in evaluating patients for internal joint derangements. The applicability of magnetic resonance imaging in the diagnosis of internal derangements will be discussed.