Introduction: Multiple Sclerosis (MS) is a chronic disease of the central nervous system and one of the most common neurological disorders among young adults. Clinical manifestations of MS vary from a benign disease to a rapid progressive disabling disorder. Although headache is not common in MS, an increased incidence of headache has been reported in people with MS. According to high prevalence of primary headache in MS patients and the prominence of its diagnosis in improving the quality of life, our aim was to evaluate the frequency of primary headache in patients with MS. Materials and Methods: 100 patients with multiple sclerosis enrolled in this descriptive study. Age, gender, clinical form of disease, duration, Expanded Disability Status Scale, family history of headache and type of headache according to international headache society criteria (IHS) were recorded. Results: In this study, 48% of MS patients had primary headache. Frequency of migraine was 19% and tension type headache was 29%. There was no significant association between primary headache and MS clinical features. Conclusion: This study points to a high comorbidity of headache and MS in Mashhad. Further studies in larger number of patients are needed to confirm our preliminary investigations.