This paper describes the development and testing of the UK version of the Migraine-Specific Quality-of-Life instrument (MSQOL), a measure designed to assess the quality of life of migraineurs. The work was part of an international research study conducted in eight countries, with the initial development work conducted in the UK and the USA. In the UK, interviews were held with 30 patients with migraine, while in the USA, 25 individual interviews were conducted, along with one focus group with 5 participants. Transcripts were produced of the interviews/group discussion and these were used to determine the questionnaire items, which were then considered by an international translation panel. The panel considered the feasibility of translating the items into other European languages. The instrument was then assessed for reliability and validity. The UK version of the MSQOL was shown to have excellent test-retest reliability (0.93 over 2 weeks) and internal consistency (0.92 and 0.93 on the first and second administrations, respectively). Scores on the measure were also found to be related to a comparator measure of well-being and to perceived severity of migraine and disruption caused to patients by the disease. Findings for the other language versions of the MSQOL supported those from the UK, suggesting that the instrument may well be suitable for inclusion in clinical trials.