The aim of this study was to evaluate the short-term effect of the botulinum toxin type A injection for the treatment of myofascial pain dysfunction syndrome. Fifteen patients suffering from myofascial pain dysfunction syndrome were included in this study. The patients were selected from the out-patient clinic of oral and maxillofacial surgery department, Faculty of Oral and Dental Medicine, Cairo University.All masseter and temporalis muscles were injected with 20-30 Units of BTX-A respectively and followed up for three months.Follow up assessment included on clinical measurements of maximal inter-incisal opening, range of lateral movement and visual analogue scale for pain. EMG images were ordered pre-operatively and at the end of 3 months period to quantify any changes in muscle activity.Results of the present study showed clinical disappearance of pain in all patients upon completing the follow up period.