Objective: Inflammatory bowel disease [IBD] entails a high economic burden to society. We aimed to estimate the current and future impact of the introduction of biosimilars for infliximab on IBD-related health care costs. Methods: We designed a stochastic economic model to simulate the introduction of biosimilars in IBD, using a 5-year time horizon, based on the Dutch situation. Prevalence data on ulcerative colitis [UC] and Crohn's disease [CD] and IBD-related health care costs data were used as input. Assumptions were made on price reductions of anti-tumour necrosis factor [TNF] therapy, increase of anti-TNF prescription rate, and development of hospitalization costs. The base case scenario included a gradual decrease in prices of biosimilars up to 60%, a gradual decrease in prices of original anti-TNF compounds up to 50%, and an annual increase of anti-TNF prescription rate of 1%, and this was compared with no introduction of biosimilars. Sensitivity analyses were performed. Results: For the base case, cost savings over the total of 5 years were on average (sic)9,850 per CD patient and (sic)2,250 per UC patient, yielding in (sic)493 million total cost savings [a reduction of 28%] for The Netherlands. Results were predominantly determined by price reduction of anti-TNF therapy, threshold price reduction at which physicians switch patients towards biosimilars and the extent to which switching will take place. Conclusions: The introduction of biosimilars for infliximab can be expected to have a major impact on the cost profile of IBD. The economic impact will depend on local pricing, procurement policies and the physician's willingness to switch patients to biosimilars.