A questionnaire to assess quality of life in the elderly was developed under the auspices of the European office of the World Health Organization. Stages in construction of the instrument, which was designed for international application, particularly at the primary level, are described. The latest version of the questionnaire is composed of 49 self-assessment item, 31 of which can be grouped into 7 subscales: Physical Function, Self-Care, Depression and Anxiety, Cognitive Functioning, Sexual Functioning, and Life Satisfaction. The remaining 18 items serve as moderators for assessing the influence of social desirability factors and personality characteristics on the individual scores for the 7 core instrument subscales. The questionnaire has been administered to 586 individuals aged 65 years and over recruited in communities in Italy (Padua and Brescia), the Netherlands (Leiden), and Finland (Helsinki). The main psychometric characteristics of the instrument, together with its concurrent validity with the Rotterdam Questionnaire, are illustrated.