The EQ-5D is a standardised preference-based instrument to measure health-related quality of life (HRQoL). It provides a simple descriptive profile and a one-dimensional index score for health status. Designed for self-completion by respondents, the EQ-5D can be used in population health surveys, clinical studies and economic evaluation of health care. The EQ-5D descriptive system consists of five dimensions (mobility, self-care, usual activities, pain/discomfort and anxiety/depression), each of which comprises three levels (no problems, some or moderate problems, extreme problems or unable). This information can be used as an EQ-5D health profile for individuals or groups. Moreover, the descriptive information can be converted into a one-dimensional index score, using scoring functions based on value sets elicited from general population samples. Sets of values are available for several countries, including the United Kingdom, the United States and Germany. A comparison of different value sets suggests that values are related to cultural differences. Thus, where EQ-5D value sets for the relevant population exist then this set should be used index scores for use in national health-economic evaluation studies this country-specific value sets can be applied to provide EQ-5D preference weights for use in health-economic evaluation studies. Recently, the EuroQol Group derived a European value set, based on data collected in six Western European countries (Finland, Germany, The Netherlands, Spain, Sweden and the UK). Scores based on the European scoring function can be used in multinational studies.