Temporomandibular joint (TMJ) arthrography is a highly accurate diagnostic modality for the internal derangement of TMJ including disc perforation. Tears or perforations of the disc are easily recognized when simultaneous filling phenomenon of the upper joint space (UJS) occurs with injection of contrast material into the lower joint space(LJS). But the reported incidence of false positive cases of perforation in about 15-20% So authors analyzed 34 patients with TMJ dysfunction and 5 volunteers and evaluated disc peforation and its pitfalls. The following results noted: 1. We got 5 true positive and 2 false positive cases of disc perforation and 1 experimental case could show the possible genesis of the pseudo-perforation phenomenon. 2. Very important diagnostic points of disc perforation were the visible perforation site the absence of penetration of the lateral recess of UJS during the puncture of LJS and absence of penetration of the lateral recess of UJS during the puncture of LJS and accompanying severe bony and disc degenerative changes. 3. Tehchnically to minimize the incidence of artificial perforation the mouth motion and excessive contrast filling should be avoided during injection of LJS.