OBJECTIVE: The Benign Prostate Enlargement-Partner questionnaire (BPE-P) was initially developed to assess the impact of patient's Benign Prostatic Hyperplasia (BPH) on his partner's quality of life (QOL). The objective of this study was to adapt the BPE-P for use in the clinical trial setting, and to linguistically validate the resulting questionnaire in US, Spanish, Canadian English and Canadian French subjects. METHODS: The BPE-P was reworded to facilitate use in a clinical trial, and reviewed by a multidisciplinary team including clinicians, QOL experts, and linguists. This US English version was translated according to standard methodology: 2 forward translations, 1 reconciliation, 1 back-translation by a native English-speaker, 3-4 reviews by independent bilingual experts, and final reconciliation by a native-speaking language coordinator. Pilot testing and cognitive debriefing interviews were performed with a minimum of 10 subjects per language/country who were partners of men with BPH. RESULTS: The following changes were made to the questionnaire prior to translation: a) recall period of 30 days was incorporated; b) questions were changed to past tense to reflect the recall period; c) wording on problems with sex life was changed to sexual satisfaction to better suit the trial setting and to prevent a response floor effect; d) responses to the sexual satisfaction and overall QOL question were revised; e) sexual satisfaction question was moved to the penultimate item on the scale to better suit the flow of questions. No significant problems were detected during translation. Subjects found the translations and their content suitable and relevant to their situation. The resulting instrument is now called the Benign Prostate Enlargement- Partner Impact of Treatment scale (BPE-PIT) to better reflect its adaptation to the clinical trial setting. CONCLUSION: The BPE-PIT was successfully translated for use in an international clinical trial. Psychometric validation of this new instrument remains necessary.