BACKGROUND AND AIMS: Inflammatory Bowel Disease (IBD) is known to impact patients' sexual lives. The aim of this study is to create and validate a sexual quality of life (QoL) designed for youth with IBD. METHODS: This study was conducted in 2 phases: development of the score and validation of the items. A multidisciplinary team created a score called BLOOMI, based on 2 validated scores: the International Index of Erectile Function (IIEF) and the Sexual Function Questionnaire 28 (SFQ28). It was validated through a French multicentric cross-sectional study among patients aged 15-25 years with IBD by comparison with IIEF and SFQ28 gold standard scores. RESULTS: BLOOMI is a sexual QoL designed with 10 items and formatted as a disk. The score was validated through the participation of 104 patients with a median age of 23.2 years. BLOOMI was well correlated with both gold standards and had a strong internal consistency. In total, 19.1% of IIEF-responders have erectile dysfunction and median scores for the SFQ domains Desire, Arousal sensation and cognition, and orgasm are below the threshold for the absence of sexual dysfunction. Fatigue, abdominal pain, body image concerns, or fear of anal leakages are correlated to a poorer sexual QoL. CONCLUSIONS: The BLOOMI score is a newly validated score to assess the sexual QoL in 15-25 years with IBD. This tool may improve the screening for sexual challenges encountered by youths with IBD and may support future research into the impact of IBD on young patients' lives.