There is need for multilingual cross-culturally valid quality of life (QOL) instrumentation to assess the QOL endpoint in international oncology clinical trials. We therefore initiated a multilingual translation of the Functional Assessment of Cancer Therapy (FACT) Quality of Life Measurement System (Version 3) into the following languages: Dutch, French, German, Italian, Norwegian and Swedish. Prior to this project, the FACT Measurement System was available in English, Spanish and Canadian French. The FACT is a self-report instrument which measures multidimensional QOL. The FACT (Version 3) evaluation system uses a 29-49 item compilation of a generic core (29 Likert-type items) and numerous subscales (9-20 items each) which reflect symptoms associated with different diseases, symptom complexes and treatments. The FACT-G (general version) and eight of 18 available cancer-related subscales were translated using an iterative forward-backward translation sequence. After subsequent review by 21 bilingual health professionals, all near final language versions underwent pretesting with a total of 95 patients in the native countries. Available results indicate good overall comprehensibility among native language-speakers. Equivalent foreign language versions of the FACT will permit QOL evaluation of people from diverse cultural backgrounds.