OBJECTIVE: To study the outcome of oral appliance treatment in myofascial Temporomandibular disorder (TMD) patients with and without comorbid pain using pain site drawings. MATERIAL AND METHODS: This randomized, controlled multicentre study comprised 65 myofascial TMD patients diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders. Pain-site drawings were filled in at the baseline examination. The patients were treated with oral appliances. Treatment outcome was followed up for 1 year and analysed according to the recommendations by the Initiative on Methods, Measurement and Pain assessment in Clinical Trials (IMMPACT) on an intent-to-treat basis. The data were analysed for two pain profiles, localized pain (face and head, n = 26) versus widespread pain group (pain sites outside the face and head, n = 39). RESULTS: Statistically significant improvement was registered within both groups for all outcome variables (characteristic pain intensity, 30% pain reduction of worst reported pain, graded chronic pain, depression, and somatization scores) during the follow-up with only small differences between the groups. CONCLUSIONS: Oral appliance treatment had a positive effect on all outcome measures during the 1-year follow-up in patients suffering from myofascial TMD pain, regardless of whether the pain was localized or widespread. Multiple pain sites seemed to have surprisingly little influence on the outcome variables. However, some indications of more challenges when treating patients with widespread pain compared to local pain could be observed. Pain-site drawings seem to be useful in the clinical situation and could support the clinicians in decision-making regarding treatment planning.