A retrospective study of 498 patients (591 joints) who had diagnosed as having internal derangement of the temporomandibular joint by history, clinical examination, and arthrography were evaluated. 66 patients (70 joints) were diagnosed as having meniscus perforation between the joint compartments. In those patients with pain (11 joints : 15.7%), pain and crepitation (24 joints : 34.3%), pain, crepitation and LOM (31 joints : 44.3%), and painless crepitation with LOM (4 joints : 5.7%) complained clinically. All these patients who had perforation showed irregularity in outline of the contrast material, bone contour-contrast material gaps, flattening of cortical layer of articular eminence. On the 20 joints treated surgically, 17 joints were found to have meniscus perforation at the time of surgery which correlated with their pre-operative radiographic and clinical diagnosis. Three joints could not found perforation of meniscus. This study was designed to examine of the incidences of the meniscus perforation in the above patients and to assess the diagnostic accuracy of arthrography by comparing the results with the finding of direct examination at TMJ surgery.