Microscopic colitis (MC) is a chronic inflammatory disease of the colon that presents with chronic, nonbloody watery diarrhea and only few or no endoscopic abnormalities. Histologic examination discriminates lymphocytic colitis (LyC; presence of ≥20 intraepithelial lymphocytes per 100 surface epithelial cells) and collagenous colitis (CC; colonic subepithelial collagen band >10 μm in diameter). ¹ ^, ² MC not otherwise specified describes a subgroup of patients who do not fulfill the diagnostic criteria for either CC or LyC. ¹ ^, ² Population-based epidemiologic data regarding MC are scarce. We aimed to evaluate the clinical presentation at diagnosis, incidence, and prevalence of MC in Cantons of Vaud and Fribourg, Switzerland.