Abstract: A number of classifications of headache have appeared in medical and professional journals. In addition to these formal diagnostic classifications, a number of articles have addressed the relationship of sexual functioning to headache etiology, course, and prevalence. To this end, many headache specialists have developed a classification for what are termed ‘sexual headaches.’ To date, these sexual headaches have been limited to migraine and muscle contraction (tension) headaches patterns. We present, for the first time, two case studies documenting the role of sexual activity in both etiology and course of cluster headache.