Background: The two main types of inflammatory bowel diseases [IBD] are --Crohn's disease [CD] and ulcerative colitis [UC]. Only limited data are available regarding the diagnostic accuracy of fecal matrix metalloprotease-9 [MMP-9] for inflammatory bowel disease [IBD]. Aim of the Work: the aim of our study was to assess the diagnostic role of fecal MMP-9 in patients with active CD and UC and its accuracy in predicting the disease remission Patients and Methods: This case-control study was conducted at Ain Shams University Hospitals, Cases were enrolled over 9 months from june - 2022 to february - 2023. This study was performed on 80 subjects divided into 3 groups: Group A: 30 patients with Crohn's disease evidenced by endoscopy (ileocolonoscopy and upper GI endoscopy) and tissue biopsy 15 patients with active disease & 15 patients in remission). Group B: 30 patients with Ulcerative Colitis disease evidenced by colonoscopy and tissue biopsy (15 patients with active disease & 15 patients in remission). Group C: 20 age-matched, sex-matched healthy controls Results: FC can significantly assess CD and UC (AUC = 0.991 for CD and 0.996 for UC at cut off >743 mg/g for CD and >245 mg/g for UC, 93.33% sensitivity, 100% specificity, 100% PPV and 93.7 NPV (P value <0.001). Fecal MMP-9 can significantly assess CD and UC (AUC = 0.998 for CD and 0.991 for UC at cut off >0.34 ng/mL for CD and >0.36 ng/mL for UC, 93.33% sensitivity, 100% specificity, 100% PPV and 93.7 NPV (P value <0.001); Conclusion: this study assesed the diagnostic accuracy of fecal MMP-9 in the different types of IBD. The results showed that fecal MMP-9 has high sensitivity in the detection of endoscopically active UC and CD, and these non-invasive methods help in assessing intestinal inflammation. [ABSTRACT FROM AUTHOR]