Introduction This study was conducted to determine the effectiveness of ultrasonographic imaging for diagnosing temporomandibular joint internal derangements. Materials and methods Ultrasonographic and magnetic resonance imaging scans of temporomandibular joints were obtained bilaterally in 55 patients who had temporomandibular joint disorders and who were diagnosed with temporomandibular joint internal derangements following a clinical examination. Diagnostic accuracy of ultrasonographic imaging was assessed considering magnetic resonance imaging as the gold standard method. Results When the results of ultrasonographic imaging and magnetic resonance imaging were compared, the diagnostic accuracy of ultrasonographic imaging was 0.81 for detecting TMJ disc displacement. The diagnostic accuracy of ultrasonographic imaging in detecting TMJ disc position was 0.81 in the closed-mouth position and 0.93 in the open-mouth position. Conclusion As a noninvasive and reproducible imaging method acquiring dynamic images, ultrasonographic imaging is a successful method in the evaluation of temporomandibular joint disc displacement.