Intro: Inflammatory bowel disease (IBD), consisting of ulcerative colitis (UC) and Crohn’s disease (CD), leads to chronic intestinal inflammation associated with significant morbidity. The underlying mucosal dysregulation is not entirely understood, and many patients are refractory to available medical therapy. Defining inflammatory and disease-specific immune signatures would improve our understanding of IBD and help identify novel biomarkers and targets for treatment. We used mass cytometry (CYTOF) to profile colonic lamina propria (LP) and peripheral blood (PB) mononuclear (MN) cells of patients with IBD as well as non-IBD controls.