Quality of life has become an important end point in clinical trials and academic studies. The questionnaires developed by the European Organisation for Research and Treatment of Cancer Quality of Life Group are widely used to measure quality of life in cancer patients. The expanding geographical coverage of current studies and trials implies a continuous rise in requests for new language versions of the questionnaires. Together with normal linguistic problems in translation, cultural differences come into play, especially in translations into non-European languages. Two types of such problems can be differentiated: first, specific issues related to culturally dependent activities or phenomena; second, topical issues related to taboos. These translation challenges have to be carefully addressed to ensure the equivalence and validity of the final questionnaires.