Background: The co-occurrence of MDS and IBD has been gradually recognized in the literature. Yet, large-scale national studies are required to investigate this observed association further. We aimed to delineate the clinical features, outcomes between the concurrent of MDS with IBD and MDS or IBD alone in a nationally representative database. Methods: Data were obtained from the NIS 2010-2014, using appropriate ICD-9 codes to identify patients who were admitted with a principal diagnosis of MDS with IBD as secondary (MDS-1/IBD) and MDS without IBD and patients who were admitted with a principal diagnosis of IBD with MDS (IBD-1/MDS) and without MDS. We assessed the mortality rate as the primary outcome, mean length of stay (LOS), and rate of blood transfusion as secondary outcomes by Pearson χ2 -test and univariate regression (logistic regression). Results: We identified 190 hospitalizations for MDS-1/IBD and 4895 hospitalizations for IBD-1/MDS. The mean LOS was higher for MDS-1/IBD group than for IBD or MDS only (11.7 vs. 6.1 and 7 days). However, the mortality rate in the MDS-1/IBD group was lower than in patients with IBD or MDS only (2.6% vs. 3.8% and 4.4%). While the rate of blood transfusion was higher among males in the MDS group, it was significantly higher among females when there is a concurrent MDS-1/IBD. However, the differences were not significant when MDS is not the primary diagnosis i.e IBD-1/MDS. In univariate analysis, age and Charlson comorbidity index were significantly associated with an increased mortality rate when there are IBD and MDS than MDS or IBD alone. Conclusions: While unable to assess appropriateness, NIS data indicate that there are significant differences in outcomes such as mean LOS, rate of blood transfusion and mortality rate when there is a concurrence of MDS and IBD than MDS or IBD alone. The underlying pathogenicity remains unclear and warrants additional study.