Temporomandibular joint disorder (TMJ) is a complex and multifactorial functional disorder. Best approach in the treatment of TMJ disorders needs in detail proper diagnostic study. Joint vibration analysis (JVA) device, a new age technology and one of the most important diagnostic tools, is used for detecting intra-articular sound vibrations. Every type of vibration in different frequencies shows us the status of joint. Evaluation can be made after analyzing the results applying to a diagram. Like Combining of the sound vibration diagnostic techniques with other examination methods may be very meaningful in efforts of treating TMJ problems. Another diagnosis method is the evaluation of chewing movements. Best chewing efficiency is the most important purpose of masticatory system. Final product is a very important indicator for the efficiency of the mastication, and chewing pattern. T-Scan digital occlusal analyzing system is another important occlusal diagnostic instrument. Digital occlusal analysis system is currently the most powerful method of TMD clinics for treatment of patients with muscle pain dysfunction syndrome. Digital occlusal analysis system allows us to perform the MPDS treatments, splint and occlusal rehabilitation. The three important diagnostic systems are described in this chapter.