A case of posterior disk displacement (PDD) without reduction of the temporomandibular joint (TMJ) was observed in this case report. The disk position was altered by using an occlusal splint and intermaxillary elastic traction for 1 0 days. An anterior displaced disk with reduction (ADDw/R) resulted from this therapy. Proposed criteria for diagnosing the PDD without reduction of the TMJ will be discussed in this study.