The Women's Health Questionnaire (WHQ) is a measure of mid-aged women's emotional and physical health. Since its publication in 1992 the WHQ has been widely used in multinational clinical trials, in epidemiological studies as well as in the evaluation of non-medical treatments. In particular the WHQ has been included as a quality of life measure in trials of hormonal preparations for peri and post menopausal women and in studies using a variety of preventative interventions for mid-aged and older women. The questionnaire was developed in English and standardised on a sample of women aged 45-65 years. It is reliable, has good concurrent validity and is sensitive to detecting change, and is available in 27 languages. The range of subscales included in the WHQ enable a detailed assessment of dimensions of emotional and physical health, such as depression, anxiety, sleep problems, somatic symptoms, with optional subscales for menstrual problems and sexual difficulties. The WHQ is the first measure to be included in the MAPI Research Institute's database, the International Health-related Quality of Life Outcomes Database (IQOD). Drawing upon data from international studies this project aims to produce reference values for cross-culturally valid, reliable and responsive quality of life instruments. In addition to this work, a revised shorter version of the WHQ is currently being developed.