Background and aims: inflammatory bowel disease development has been associated with several environmental factors, among which, diet can play a key role, probably due to a westernized lifestyle. However, its involvement in the pathogenesis of inflammatory bowel disease (IBD) is difficult to demonstrate. The aim of this study was to analyze dietary composition in a Romanian and Belgian population with IBD. Methods: An observational retrospective comparative study was performed using two European cohorts (Romanian and Belgian). The IBD group included 76 Romanian and 53 Belgian patients with an IBD diagnosis, while the control group included a total of 56 healthy people (35 Romanians and 21 Belgians). All subjects were interviewed and asked to fill in a questionnaire regarding diet. Results: in the entire IBD cohort (Romanian + Belgian), a significantly increased consumption of sweets (OR 3.36 [95 % CI 1.6,7]), processed and high fat meat (OR 2.5 [95 % CI 1.4, 4.7], fried food (OR 9.5 [3.8, 23.6]), salt (OR 2.8 [1.5, 5.3]), ice cream (OR 3.25 [1.1, 9.8]), mayonnaise (OR 3.49 [1.1, 10.3]), margarine (OR 5.63 [1.64, 19.33]) and chips/nachos/other snacks (OR 2.3 [0.97, 5.73]) were found compared to the healthy control group. The intake of seeds, nuts (OR 0.26 [0.14, 0.52]) and yoghurt consumption (OR 0.44 [0.23, 0.83]) was lower in the IBD group compared to the control group. Conclusion: A westernized diet with increased consumption of sweets, processed food, high fat meat, fried food, salt, margarine, snacks, ice cream and mayonnaise seems to be a risk factor for IBD in Romanian and Belgian IBD patients. Intake of seeds, nuts and yoghurt may be a protective factor. © 2020. SEPD y © ARÁN EDICIONES, S.L. ; WBI SUB/2018/388156