Introduction: Migraine and temporomandibular disorders (TMD)are both common diseases and TMD are reported as a risk factor inmigraine progression. OnabotulinumtoxinA is used in the treatment ofchronic migraine (CM), and also has a potential role in TMD treatment.In this study, it is aimed to compare the efficacy of onabotulinumtoxinAtreatment in CM patients with and without TMD.Methods: In this retrospective study, 30 CM patients (age range: 18–65years), satisfying the inclusion and follow-up criteria in their medicalrecords were investigated. The PREEMPT injection protocol was takenas reference and onabotulinumtoxinA 155–195 U with fixed-dose hasbeen administered into 31 specific sites within the head/neck muscles inincluded subjects. Two cycles of treatment were assessed in all patientsat the baseline and 12 weeks later. The headache diaries, which werecompleted routinely one month before, and during 6 months followupafter the treatment, were assessed. The effect of onabotulinumtoxinAtreatment was compared between CM patients with and without TMD/bruxism.Results: Of 30 female patients, 17 had concomitant TMD. In week 24,there were significant improvement in the groups with and without TMDregarding to the mean change of frequencies in the days with migrainecompared to the initial findings (p<0.001). However, there was nosignificant difference between the two groups.Conclusions: OnabotulinumtoxinA is an effective and safe treatment forCM. Its efficacy appears to be similar in CM patients with and withoutTM, speculating that the comorbidity of TMD did not play a role for thetreatment response.