Causes of inflammatory bowel diseases are not well understood and the most prominent forms Crohn’s disease (CD) and ulcerative colitis (UC) are sometimes hard to distinguish. Glycosylation of immunoglobulin G (IgG) has been associated with CD and UC. IgG Fc-glycosylation affects IgG effector functions. We evaluated changes in IgG Fc-glycosylation associated with UC and CD, as well as with disease characteristics in different patient groups.