A 42-year-old man came to our headache unit in October 1995 complaining of recurrent attacks of headache, which had begun in February 1991. Chronic cluster headache was diagnosed, and he was given verapamil, 360 mg per day. The attacks ceased in the following months and verapamil was stopped in March 1996. In May 1997, a recurrence of the attacks required the readministration of verapamil, 360 mg per day. The attacks decreased (one to three per week), but after 2 months the patient reported a worsening in his condition due to the appearance of shorter attacks, which were diagnosed as chronic paroxysmal hemicrania. The administration of indomethacin, 225 mg per day, resulted in the disappearance of the short attacks. The concomitant occurrence of attacks of cluster headache and chronic paroxysmal hemicrania suggests the presence of shared factors in the pathophysiology of the two forms of headache. This hypothesis is supported by previous reports in the literature.