Differential diagnosis between Ulcerative Colitis (UC) and Crohn's disease (CD) is of pivotal importance for the management of Inflammatory Bowel Disease (IBD) as both entities involve specific therapeutic management strategies. Confocal Laser Endomicroscopy (CLE) allows on demand in vivo characterization of architectural and cellular details during endoscopy. Here, we assessed the efficacy of CLE to differentiate between UC and CD.