With the increased number of multinational clinical trials and epidemiological studies using Patient-Reported Outcomes (PRO), the need of cross-cultural reference values for analysis and interpretation has arisen. OBJECTIVE: The International Health-related Quality of Life Outcomes Database (IQOD) Programme aims at creating scores and standardizing analysis and interpretation for health-related quality of life questionnaires. METHODS: Data were collected from multiple clinical trials and epidemiological studies conducted worldwide. The IQOD Programme Phase I involves the Women's Health Questionnaire (WHQ), the Psychological General Well-Being Index (PGWBI), and the Minnesota Living with Heart Failure Questionnaire (MLHF). These instruments represent three types of PRO: generic, condition, and disease specific instruments, selected for their linguistic adaptation into several languages, their reliability and validity, and their extensive use. Descriptions of population, analysis and interpretation provide reference values in different population groups and per country. RESULTS: Data collection and specification include the elaboration of the merging rules in order to incorporate the results of multiple studies while building the databases. 1) IQOD-WHQ collected data among 9023 women (mean age: 52 years), using the 37-item version of the WHQ, were analysed and interpreted. Pre, peri and post-menopausal women reference values have been established for 6 languages, 10 European countries and USA. WHQ's scoring has been reviewed with the author and a 23-item short-form WHQ has been developed. IQOD-PGWBI database includes data of 11 286 patients (mean age: 46 years) living in 19 countries, speaking 15 languages with symptomatic GERD, HTA, chronic constipation, colorectal cancer, digestive problems and several co-morbidities. IQOD-MLHF data collection is being finalized. CONCLUSION: IQOD-WHQ and IQOD-PGWBI databases analysis provides reference values for comparison of PRO data across populations (countries and languages), cultures and condition severity. Ongoing and future work in IQOD focus on creating similar reference values for IQOD-MLHF and other PRO.