This study was designed to evaluate the diagnostic effect of the simulatneous multifilm individualized lateral tomography in the diagnosis of the temporomandibular disorders. The subjects consisted of 29 patients with symptoms of the temporomandibular disorders. The panoramic view, oblique lateral transcranial radiograph (OLTC) (Hirozontal angulation 0°, Vertical angulation 29°), submentovertex view, and simultaneous multifilm individualized lateral tomographs (SMFI) in centric occlusion (2.5㎜ thickness difference, 5 layers) were taken for the patients. This study compared the findings from each radiographs in the determining of mandibular condylar position with dual linear measurement of the subjective closest posterior and subjective closest anterior interarticular space and in the determining of bony changes on the studied 30 temporomandibular joints (TMJ) with symptoms of the temporomandibular disorders. The results were as follows: 1. The distribution of condylar position of OLTC and 5 layers of SMFI depended on the radiographs (p<0.05). The condylar position and the distribution of condylar position of OLTC were more similar to lateral sections of the SMFI than mesial sections, and in the distribution of the condylar position of SMFI, the more lateral sections of SMFI, the more concentric 2. positions. There were 10 cases in which all layers showed the same condylar position as that of OLTC. There were 3 cases in which no layers showed the same condylar position as that of OLTC. 3. In the SMFI of 30 Temporomandibular joints studied, there is 13 cases in which all five layers represented the same condylar position in the same TMJ and 11 cases in which 4 layers represented the same condylar position in the same TMJ and 6 cases in which 3 layers represented the same condylar position in the same TMJ. So at least 3 layers of SMFI represented same condylar position in the same TMJ. 4. The bony changes were not detected in conventional radiographs on the temporomandibular joint and the bony changes were not detected in simultaneous multifilm individualized lateral tomographs. The bony changes were detected in conventional radiographs on the temporomandibular joint and the bony changes were detected in simultaneous multifilm individualized lateral tomographs. SMFI provided a meams for a three dimensional visualization of the shape, the position and the extent of bony changes of TMJ.