Inflammatory diseases are accompanied by numerous changes at the site of inflammation as well as many systemic physiological and biochemical changes. In the past two decades more and more attention is being paid to changes in glycosylation and in this review we describe some of the changes found on main serum proteins (alpha1-acid glycoprotein, immunoglobulin G, immunoglobulin A, transferrin, haptoglobin, alpha2-macroglobulin, C-reactive protein, and others). Molecular background and physiological importance of most of these changes are yet to be discovered, but it is evident that glycosylation plays an important role in the inflammatory response. Maybe the greatest value of these changes currently lays in their potential diagnostic and prognostic usage, either in combination with current diagnostic markers or on their own. However, determining glycan structures is still technically too complex for most clinical laboratories and further efforts have to be made to develop simple analytical tools to study changes in glycosylation.