The frequency and characteristics of headache in patients with chronic obstructive pulmonary disease (COPD) are not clear and there are only a few studies that have assessed the relationship between chronic hypoxaemia and headache. We performed this study in order to evaluate the frequency and characteristics of headache in COPD patients. A total of 119 patients, with a mean age of 63.4 +/- 8.2 years, diagnosed with moderate or severe stable COPD were included in the study. Overall 31.9% of the patients complained of headache and 45.4% were reported to have sleep disorders. There were significant effects of family history of COPD, having other systemic disorders or sleep disorders (snoring, bruxism, restless leg syndrome, etc.) and laboratory data of chronic hypoxaemia and airway obstruction on headache co-morbidity. In conclusion, possibly being a specific subtype of elderly headache, headache in patients with moderate or severe COPD is a common problem and future studies are needed to obtain more knowledge about its pathophysiological and clinical basis.