OBJECTIVES: The objective of this study was to evaluate the linguistic validity of 10 translations of the Nocturia Quality of Life (N-QOL) questionnaire. This self-administered questionnaire was originally developed in English (UK) to measure the impact of nocturia on health-related quality of life in men with lower urinary tract symptoms (LUTS), and has since been validated for use in women. METHODS: Harmonized translations of the questionnaires were created through an internationally accepted reiterative process of forward and back translations and review by a survey research expert and local study users for the following languages: Afrikaans (South Africa), Chinese (Taiwan), English (Canada), English (South Africa), English (USA), French (Canada), Korean (Korea), Spanish (Mexico), Swedish (Sweden), and Turkish (Turkey). All translators were native speakers of the target language and fluent in English (UK). A diverse sample of 5 subjects in each language reviewed the harmonized translations and was subsequently debriefed by trained bilingual interviewers, fluent in both English (UK) and the target language. A team consisting of the original translators, back translator, project manager, interviewer, and survey research expert evaluated all conceptual, linguistic and stylistic issues that emerged from the debriefings. RESULTS: Overall, the translations were well understood by subjects in all languages. Subjects in several countries had mild difficulty understanding the terms “Nocturia”, “preoccupied”, and “quality of life”, although these concepts were translated appropriately in all languages. The term “concentrate” (“konsantre”) also posed difficulty for Turkish translators and subjects. As there is no other contextually appropriate Turkish word for this concept, no change was made to the Turkish translation. CONCLUSION: The 10 translations of the NQoL instrument are linguistically and conceptually equivalent to the original English (UK) questionnaire. Linguistic validation of the translations will facilitate inter-country comparisons of nocturia and the pooling of data in multi-country studies.