Abstract INTRODUCTION Inflammatory bowel diseases (IBD) are gastrointestinal (GI) conditions associated with significant costs. Effective management of IBD should focus on improving patient symptoms and outcomes while containing healthcare costs. To develop high-value treatment strategies and influence policy on high-value care, we must first have a better understanding of the primary drivers of cost in this population. METHODS We conducted a real-world descriptive cohort study using data from IBM Watson, which is a nationwide insurance claims database covering millions of commercially insured individuals across the US. We identified adult patients aged 18 to 65 years with encounters associated with a diagnosis of IBD in the primary or secondary position from January 2019 to January 2020 based on ICD-10-CM codes for Crohn's disease (555.x) and ulcerative colitis (556.x). Analysis of IBD prevalence, costs, and service utilization was based on ICD, CPT, and NDC codes related to IBD conditions and services. All other codes without an associated GI diagnosis in the primary or secondary position were attributed to all-cause costs. Measures of cost and utilization were calculated as a per member per year (PMPY). RESULTS 105,496 patients with IBD were identified (Table 1). The mean PMPY total costs were $40,842 of which $31,051 (76%) were directly related to GI-related costs. Mean PMPY total costs in this population ranged from $1,178 to $144,945, with 15% of members experiencing costs > $76,346 PMPY. The main drives of GI-related costs can be divided into the following three categories: Inpatient costs ($8,206 [26%]), outpatient medical service costs ($11,306 [36%]), and drug costs ($11,539 [37%]) (Table 2). Per member utilization includes: 0.22 inpatient admissions, 0.10 surgeries, 1.02 GI visits, 2.87 non-gastroenterologist GI visit (which could include a visit to a primary medical doctor, rheumatologist, dietician, etc), 4.57 GI-testing, 0.48 GI imaging, 0.61 GI endoscopy, and 1.07 biologic medication prescriptions. CONCLUSIONS IBD care carries a significant financial burden on the US healthcare system. Unplanned emergency service and medication utilization continue to make up the majority of costs of IBD care and need to be the focus of value-based interventions. While appropriate high-cost pharmaceutical utilization should not be reduced, innovative strategies leveraging more cost-effective medication delivery may provide an important opportunity to curb costs. Furthermore, the high rate of non-gastroenterologist GI visits suggests that there is a potential for optimizing care pathways, by incorporating multidisciplinary care including, PCPs, mid-level providers, and other ancillary services into the IBD care model.