BACKGROUND: the last 20 years have seen the development of hundreds of health-related quality of life (HRQL) instruments which are increasingly being used in multi-national clinical trials. As a result, regulatory authorities are more and more faced with HRQL as a new outcome measure for the evaluation of new therapies. In 1997, Mapi Research Institute organised an exploratory meeting which brought together HRQL researchers and European regulatory representatives. The main objective was to highlight the regulatory authorities’ concerns about HRQL evaluation in clinical trials. Two conclusions were made: 1. There is a need to rationalise the field of HRQL research and to make HRQL a credible criterion for the evaluation of new therapies by health authorities; 2. This issue can only be resolved through a better collaborative effort between key players: health authorities, HRQL researchers and pharmaceutical companies. Following these conclusions, the ERIQA Project was launched. OBJECTIVE: to provide European regulatory authorities with guidance on how to assess the quality of HRQL studies in clinical trials, and how to evaluate the validity of HRQL claims. METHODS: the project is structured in 2 phases and 4 steps. Phase I will lead to the production of 3 types of documents, and presentations to regulatory authorities: 1. A review of existing guidelines, focusing on EMEA documents; 2. A reference document, i.e. a guidance for the regulatory authorities to assess the quality of HRQL evaluation and the validity of HRQL claims; 3. Pilot guidelines in specific indications: cancer and COPD asthma. Phase II will lead to consensus conferences with key players. RESULTS: Preliminary results of Phase I will be presented. Collaboration with other similar US initiatives are also planned.