OBJECTIVES: To evaluate the psychometric properties of 10 language versions of the King’s Health Questionnaire (KHQ). METHODS: The KHQ, a 21-item instrument to assess health-related quality of life in patients with urinary incontinence and OAB, has been translated into numerous languages. Data from a multicenter, randomized, double-blind, placebo- and active-controlled trial of fesoterodine for OAB patients were analyzed to assess the psychometric properties of the KHQ in ten languages. Patients completed the KHQ at Baseline (BL) and Week 12 of treatment and bladder diaries for 3 days before each visit. Mean BL scores, Cronbach alphas, and subscale change scores were calculated for the KHQ in each language. RESULTS: Data from 839 patients were analyzed (Australia=104; Bulgaria=58; Czech Republic=55; Estonia=59; Germany=59; New Zealand (NZ)=82; Poland=84; Romania=66; Russia=81; and South Africa=191).  Mean age was 56.7±13.9 years; 80% were female; 96% were white. BL subscale scores ranged from 16.8 (General Health Perceptions [GHP]; NZ English) to 83.6 (Impact on Life; German). Six of 7 multi-item KHQ subscales (Role Limitations, Physical Limitations, Social Limitations, Personal Relationships, Emotions, and Severity Measures; exception:  Sleep/energy) generally demonstrated adequate internal consistency reliability at BL for all languages except Bulgarian, Czech, Estonian, and Russian. Cronbach alphas at follow-up ranged from 0.50 (Physical Limitations; Russian) to 0.96 (Personal Relationships; Polish).  Concurrent validity was established in all languages with moderate to strong correlations with other PRO measures (Treatment Benefit Scale, Satisfaction question) and small to moderate correlations with bladder diary variables.  All subscales, except GHP, were responsive to treatment in all languages. CONCLUSIONS: The KHQ is a psychometrically valid outcomes measure in Australian English, German, New Zealand English, Polish, Romanian, Russian, and South African English.