Abstract Background As an objective endpoint in IBD Disease-Modification Trials, measures of disability and health-related quality of life have been proposed. IBD-DISK is an easy-to-use, and self-administered analogic visual tool designed for assessing disability. However, successful dissemination of this tool will require a cultural adaptation and translation process. To date, the IBD-Disk has not been validated in Italian clinical practice. Hence, we aimed to validate the IBD-Disk in an Italian population-based cohort according to the COSMIN recommendations. Methods The IBD-Disk italian translation and validation study was a cross-sectional multicentre study conducted in 8 Italian IBD referral centres. After forward-backward translation into Italian, patients were consecutively recruited from February 2023 to October 2023. Patients completed the following questionnaires: IBD-Disk (at baseline, T0, and after seven days, T1) and IBD-Disability Index (IBD-DI) for disability, IBDQ-32, and SF-36 for quality of life. Validation included assessment of validity, reproducibility, internal consistency. We further investigated the correlation between IBD-Disk and IBD activity and clinical factors associated with IBD-Disk. Results At baseline, 513 patients (237,46.2% CD; 276,53.8% UC) completed the IBD-Disk[Table.1]. Internal consistency was excellent with a Cronbach’s α of 0.93. The intraclass correlation coefficient (ICC) was 0.94 for test-retest (T0 and T1) (p< 0.001). To evaluate construct validity, the IBD-Disk was compared with the IBD-DI, revealing a significant positive correlation (r = 0.70; p < 0.001). Furthermore, it exhibited a positive correlation with both IBDQ-32(r=0.82, p< 0.001) and SF-36(r=0.093, p= 0.035). The overall IBD-Disk median score was 32(12-52), with 219(42.7%) reporting moderate-to-severe disability (IBD-DISK ≥ 40). The IBD-Disk score was significantly higher in patients with active CD disease based on HBI ≥ 5 compared to patients with inactive disease(p < 0.001). Similarly, for UC, patients with active disease, measured with a partial Mayo score ≥2, showed a higher IBD-DISK score than those in clinical remission[Fig.1]. Additionally, moderate-to-severe disability significantly increased in female [OR =2.83; 95% CI(1,97-4,07)] and in patients with active extraintestinal manifestations [OR = 1,71; 95%CI(1,23-2,81) p=0.04]. Conclusion This study validated the IBD-Disk in a large cohort of Italian IBD patients, demonstrating that it is a valid, reliable and responsive tool for quantifying disability. This validation enables the broad implementation of IBD-DISK across Italy, facilitating its integration into the daily clinical management of IBD patients.