The purpose of this study was to investigate the radiographic images of the condylar head in clinically normal subjects and the TMJ patients using standardized projection technique. 45 subjects who have not clinical evidence of TMJ problems and 96 patients who have the clinical evidence of TMJ problems were evaluated, but the patients who had fracture, trauma and tumor on TMJ area were discluded in this study. For the evaluation of radiographic images, the author has observed the condylar head positions in closed mouth and 2.54㎝ open mouth position taken by the standardized transcranial oblique lateral projection technique. The results were as follows: 1. In closed mouth position, the crest of condylar head took relatively posterior position to the deepest point of the glenoid fossa in 8.9 % of the normals and in 26.6% of TMJ patients. 2. In 2.54㎝ open mouth position, condylar head took relatively posterior position to the articular eminence in 2.2% of TMJ patients and 39.6% of the normals. 3. In open mouth position, the horizontal distance from the deepest point of the glenoid fossa to the condyla head was 13.96㎜ in the normals and 10.68㎜ in TMJ patients. 4. The distance of true movement of condyalr head was 13.49㎜ in the normals and l0.27㎜ in TMJ patients. 5. The deviation of mandible in TMJ patients was slightly greater than that of the normals.