Patients with inflammatory bowel disease (IBD) constitute a high-risk population for malnutrition. Routine screening with standardized tools is recommended but can be challenging. Outcome data specific to IBD are sparse. We performed a retrospective cohort study (2009-2019) and electronically screened a large community-based population with IBD for malnutrition risk by extracting height and longitudinal weight, data elements used in the Malnutrition Universal Screening Tool (MUST). We used Cox Proportional Hazards regression to evaluate whether an electronic medical record (EMR)-derived modified MUST malnutrition risk score was associated with IBD-related hospitalization, surgery, and venous thromboembolism (VTE).Results: Malnutrition risk was categorized as low in 10,844 IBD patients (86.5%), medium in 1135 patients (9.1%), and high in 551 patients (4.4%). In the one year follow up period, medium and high malnutrition risk, compared to low risk, were associated with IBD-related hospitalization (medium risk adjusted HR 1.80, 95% CI 1.34-2.42; high risk adjusted HR 1.90, 95% CI 1.30-2.78) and IBD-related surgery (medium risk adjusted HR 2.28, 95% CI 1.60-3.26; high risk adjusted HR 2.38, 95% CI 1.52-3.73). Only high malnutrition risk was associated with VTE (adjusted HR 2.79, 95% CI 1.33-5.87). Malnutrition risk is significantly associated IBD-related hospitalization, surgery, and venous thromboembolism. Application of the MUST score to the EMR can efficiently identify patients at risk for malnutrition and adverse outcomes, permitting concentration of nutritional and non-nutritional resources to those at greatest risk.