The objective of this study was to evaluate how the criteria of the second edition of the International Classification of Headache Disorders (ICHD-II) and the revised criteria fit a sample of patients with chronic daily headache (CDH). One hundred and five patients with CDH in a tertiary headache centre were included. Headache was assessed using a semi-structured interview. Patients were classified according to the ICHD-II and to the new appendix criteria of the ICHD. Using the ICHDII, 91% of patients received a combination of diagnoses and 76% received only a probable diagnosis: 47% had probable chronic migraine (CM) with probable medication overuse headache (MOH), 28% had probable chronic tension-type headache (CTTH) with probable MOH, 20% had CTTH and 3.8% had CM. Using the new appendix criteria, 88.5% of patients required one diagnosis. Seventy-six percent of patients were classified as MOH, 17% had CTTH and 6.7% had CM. The classification of CDH remains controversial. Alternative criteria for CM with and without medication overuse are discussed.