Background: Headache is one of the most frequent complaints in primary care. We reviewed headache questions submitted to an electronic consultation service in Ontario to classify the types of headaches and describe the questions being asked. We also identified reasons why answers were not retrievable within UpToDate, an online clinical resource. Methods: 65 headache eConsults were further divided into 85 questions and categorized by headache type and question theme. Questions were manually searched within UpToDate to determine if they could be answered using this resource. The intent to refer the patient for a face-to-face referral after the eConsult was collected. Results: The top classifications were migraine, unclassified headache, and exertional and/or coital headache. The themes -identified were medication questions (41.7%), investigation questions (33.3%), clinical concerns despite normal neurologic exam and/or imaging (15.5%); and abnormal imaging findings (9.5%). Answers to 40.1% of the questions were not retrievable in UpToDate. The main reason for irretrievability was an unusual presentation. Only 33.8% of eConsults resulted in a face-to-face referral to a specialist. Conclusions: Although electronic resources may be useful in some cases, clinical nuances cannot be accounted for. By providing physicians with rapid access to specialists, eConsult services may obviate the need for formal, face-to-face referrals.