OBJECTIVES: Mild cognitive impairment (MCI) is a state that lies between normal cognition and dementia, and the number of cases with the condition is rising as the population ages. However, to date, no validated patient reported outcome measure (PRO) exists specifically in MCI. We report on a study to develop a PRO for use in MCI. METHODS: Semi-structured in-depth interviews were carried out with people with MCI in order to determine the questionnaire items. These interviews were audio-recorded, transcribed and content analysed. The draft questionnaire was refined following feedback from a focus group of patients with a diagnosis of MCI. Questionnaires were posted to subjects recruited from memory clinics and research databases, the completed questionnaires were analysed using factor analytic techniques to produce the final measure; construct validity was assessed by correlation with a generic patient reported outcome measure, the SF-12. RESULTS: Interviews were carried out with 23 people with MCI. 280 questionnaires were sent to subjects, with a response rate of 56% i.e.146 were included in the analysis. Factor analysis produced a 13 item measure tapping two domains of patient reported quality of life (‘Emotional Effects’ and ‘Practical Concerns’ ). Internal consistency reliability was high for both domains (alpha was 0.91 and 0.85 respectively). Both dimensions were found to be highly and significantly correlated with the Mental Component Summary score of the SF-12. CONCLUSIONS: The Mild Cognitive Impairment Questionnaire (MCQ) is a short 13 item measure developed specifically to measure patient reported outcomes in people with MCI. It was created on the basis of patient report, and has been shown to have good psychometric properties. It is likely to prove valuable in the evaluation of treatment regimes in this important and growing patient group.