At enrollment, after informed consent form will be discussed and signed, subjects will undergo complete disease assessment. In this study, 150 adult subjects with IBD will be enrolled at the Gastroenterology Department of the San Raffaele Hospital (50 patients with Crohn's disease, 50 with Ulcerative colitis not undergoing proctocolectomy, and 50 with Ulcerative colitis undergoing proctocolectomy with ileal pouch-anal anastomosis). All the patients will perform routine investigations with Ileocolonoscopy (IC), according to the current standard of care indications and ECCO guidelines, and they will be assessed by both Intestinal Ultrasound (IUS) and Trans-perineal ultrasound (TPUS). Blood and stool samples will be obtained for fecal calprotectin (FC) and C-reactive protein (CRP) measurements, respectively, as normal clinical practice. All the procedures of this study are performed routinely in clinical practice. All the procedures are performed in a single day-visit for the patient.