Segmental colitis associated with diverticulosis (SCAD) is a disease that affects colon harboring diverticula, mostly located in the sigmoid region. It has been considered a rare disease for many years, but new studies may contribute to easier recognition. Although its pathogenesis is not yet well defined, in the past SCAD has been considered a complication of diverticular disease, whilst new endoscopic, histological, and clinical data have encouraged the concept that SCAD includes pathogenetic and therapeutic aspects peculiar to inflammatory bowel diseases. We therefore describe herein current knowledge about this disease, and why it can be considered a truly autonomous entity instead of a complication of diverticular disease.