TITLE: Clinical features and complications of inflammatory bowel diseases in children treated at the Pediatric Department of the Osijek University Hospital Center OBJECTIVES OF THE RESEARCH: The aim of this study is to examine the occurrence of inflammatory bowel diseases during a given period, to examine demographic, biochemical and anamnestic factors, comorbidities and therapeutic protocols in children. STUDY DESIGN: A cross-sectional study with historical data SUBJECTS AND METHODS: The research was conducted at the Pediatric Department of the Osijek University Hospital Center at the observed period from 2019 to 2023. By reviewing the medical documentation, the following were collected: anamnestic, clinical, biochemical and endoscopic data of 61 subjects who were either diagnosed or treated for inflammatory bowel disease in the given period. RESULTS: In the observed period, 61 patients were treated, 31 of those with a diagnosis of ulcerative colitis, and 30 with a diagnosis of Crohn's disease. The total number of cases has been increasing over the years, with a peak for both diseases in 2023. 15 % of respondents had a positive family history, while 43 % were burdened with comorbidities. More than a third of the subjects had some psychological burden and were exposed to stressful factors in their environment. The most common symptoms are gastrointestinal symptoms, such as diarrhea (77 %) and abdominal pain (72 %), while bloody stool is significantly more frequent in subjects with ulcerative colitis. The most common complications were anemia and chronic fatigue, equally in both diseases. Elevated calprotectin was found in 97 % of subjects with Crohn's disease and 100 % of subjects with ulcerative colitis, while significant hypoalbuminemia and higher values of CRP, erythrocyte sedimentation and fibrinogen activity were found in patients with Crohn's disease. After confirming the diagnosis, the treatment was started according to the protocol, and remission after 6 months was achieved in 70 % of subjects with ulcerative colitis and 52 % of subjects with Crohn's disease. CONCLUSION: The incidence of inflammatory bowel diseases is increasing over the years, with a high frequency of comorbidities, but also high rates of remission. There is no significant difference between the sexes.