Heparan sulphate (HS), a ubiquitous glycosaminoglycan, is a polymer of D-glucuronic acid or L-iduronic acid and D-glucosamine (GlcA) sugars. It is synthesized in the cis-Golgi as heparan. In Golgi, final heparan sulphate is synthesized in by the action of enzymes N- and O-HS-sulphotransferases and HS epimerase. The mature HS has 50 to 200 disaccharide units. It is part of the extracellular matrix (ECM) and plays a key role in the oncogenic pathway. Deregulation of heparin sulfate metabolism is implicated in cancer progression. HS is associated with the onset of infectious diseases and inflammatory conditions. HS interaction with Aβ fibrils contributes to the pathophysiology of Alzheimer′s disease.