Crohn's disease (CD) is an inflammatory bowel illness that can affect any portion of the GI tract, including the colon. The CD is caused by an abnormal immune response to microbiota in the gastrointestinal system, and it can develop in those genetically predisposed to it. Inflammatory bowel disease, on the other hand, is well-acknowledged to be a complex condition in which intrinsic genetic factors may play a role. Cytokine genes are thought to be crucial in inflammatory bowel disease. Interleukin 18, a newly discovered proinflammatory cytokine, has lately been related to CD and other inflammatory bowel diseases. In the current investigation, 79 biopsy samples were taken from CD patients and control subjects of both sexes and ages during the period from October 2022 to March 2023 from Teaching Hospital Gastroenterology and Hepatology, Medical City, Baghdad, of the study was to determine the levels of Interleukin-18 ( IL-18), in CD individuals and compare with the healthy group and the risk of developing CD.