Indomethacin-responsive headache syndromes represent a unique group of primary headache disorders characterized by a prompt and often complete response to indomethacin to the exclusion of other nonsteroidal anti-inflammatory drugs and medications usually effective in treating other primary headache disorders. Because these headache disorders can easily be overlooked in clinical practice, they likely are more common than previously recognized. Indomethacin-responsive headache syndromes can be divided into several distinct categories: a select group of trigeminal-autonomic cephalgias, valsalva-induced headaches, and primary stabbing headache (ice-pick headache or jabs and jolts syndrome). Each category can be differentiated clinically and by the extent to which the individual headache disorders respond to indomethacin. The paroxysmal and continuous hemicranias invariably respond in an absolute manner to indomethacin, whereas valsalvainduced and ice-pick headaches may respond in an equally dramatic, but somewhat less consistent fashion. Hypnic headache recently has been described as another primary headache disorder that may respond to indomethacin.