This study was conducted to explore the association of endocytoscopy (EC) findings with inflammatory activity and clinical course in ulcerative colitis (UC). EC was conducted for mild to moderate UC 32 cases from January 2010 to August 2016. The EC findings were classified into 4 types: EC-A, regular arrangement of round to oval pits; EC-B, irregular arrangement with/without enlarged spaces between regular pits; EC-C, irregular pits in size and shape with more irregular arrangement of pits; and EC-D, disruptive or disappeared pits.