OBJECTIVES: No validated questionnaires are available for assessing symptoms and quality of life (QoL) in Italian women with lower urinary tract symptoms (LUTS). In a large multi-centre observational study of women with LUTS (FLOW- Female LUTS: Observational Study in Women), we translated into Italian and validated the long and short forms of female-specific questionnaires (ICIQ-LF and ICIQ-SF). METHODS: The validation process consisted of forward and backward translation, test of comprehension, discriminant validity, test-retest reliability. A first set of women was interviewed after they had filled in the questionnaires. A comprehension rate was built as the percentage of correctly understood questions and pre-coded answers of all items by all patients. A case-control study was then performed. Cases were women aged > 18 year affected by LUTS from at least 3 months and with negative dipstick. Controls were defined as healthy women of comparable age. All women were enrolled consecutively. In order to evaluate reliability, cases were retested after seven days and a correlation analysis was performed between the first and the second measurement (Pearson's r). Discriminant validity was assessed by comparing the scores of cases and controls with ANOVA. RESULTS: The comprehension rate was 99.4% for ICIQ-LF and 99.1% for ICIQ-SF. Four out of 16 patients did not correctly understand 1 item (hesitancy) of ICIQ-LF, which was changed. Cases and controls were respectively 42 and 47 (ICIQ-SF), 80 and 61 (ICIQ-LF). All the ICIQ-SF patients were valuable for test-retest, while only 25 patients for ICIQ-LF. Pearson coefficient between ratings was > 0.93 for 23 out of 48 items of ICIQ-LF and 0.96 for ICIQ-SF total score (p<0.001). Cases and controls were discriminated at ANOVA (p<0.001) with both questionnaires. CONCLUSIONS: These data show that ICI questionnaires are generally easy to understand, have a good to excellent reliability and a high discriminant validity.