Burning mouth syndrome (BMS) has been considered an enigmatic condition because the intensity of pain rarely corresponds to the clinical signs of the disease. Various local, systemic and psychological factors are associated with BMS, but its etiology is not fully understood. Also there is no consensus on the diagnosis and classification of BMS. A substantial volume of research has been focused on BMS during the last two decades. Progress has been made but the condition remains a fascinating, yet poorly understood area, in the field of oral medicine. Recently, there has been a resurgence of interest in this disorder with the discovery that the pain of BMS may be neuropathic in origin and originate both centrally and peripherally.