INTRODUCTION: Botulinum toxin has been used mainly in the treatment of muscular temporomandibular joint disorders (TMD) and hyperactivity of the masticatory muscles. It is used also as a therapeutic option to relieve pain and help in functional recovery from dental, oral and maxillofacial surgery. The aim of our study was to investigate the efficacy of botulinum toxin injection in the treatment of muscular TMD. MATERIALS AND METHODS: Of the 200 temporomandibular joint patients who applied for treatment, 25 patients with muscular dysfunction of the origin were included in the study. This patient group received drug, drug - physical therapy, occlusal splint therapy and botulinum toxin. These treatments were performed step by step. Botulinum toxin was applied, in accordance with reflex measurement in electromyography guidelines to nine patients whose results were not success from the other treatments had not been successful. Measurements were taken of bite force, pain and mouth openness. RESULTS: Sixteen patients were treated with drug-physical therapy-occlusal splint therapy, and botulinum toxin treatment was found to be successful in the case of nine patients. No side effects were observed at six months follow-up. CONCLUSION: Botulinum toxin injection for the treatment of muscular temporomandibular joint disorder is a viable treatment option in the case of patients who do not respond to conservative treatment methods.