BACKGROUND: Long term growth may be compromised in patients with Inflammatory Bowel Disease (IBD). The aims of the study were to evaluate the final height in a cohort of patients with pediatric-onset IBD with respect to genetic target and to determine factors influencing long-term growth. METHODS: This is a monocentric retrospective cohort study. All patients with diagnosed prepubertal onset IBD were enrolled. Patients were classified into two groups on the basis of the achievement of target height at time of the last follow-up. Clinical parameters were also recorded. RESULTS: 82 patients were identified: 42 with Crohn's Disease (CD) and 40 with Ulcerative Colitis (UC). The mean age at diagnosis was 11.0 (SD 4.0) years. Eighty-nine percent of patients achieved final target height. Mean difference between final and target height was -1.2 cm (SD: 5,4). No statistical significance was detected between CD and UC patients final height (p=0.16). Growth failure at the diagnosis and disease severity were the only factors associated with final height achievement failure (p=0.001 and p=0.01 respectively). CONCLUSIONS: Most part of CD and UC patients achieve the target final height. Disease severity and low height at diagnosis seem to be the two best predictive factors for low final height.