Glycosylation is a critical attribute of glycoprotein products as it has been shown that the type and degree of glycosylation can have a significant impact on the product efficacy and immunogenicity. In developing generic forms of glycoprotein based therapeutic products, it is necessary to characterize the glycosylation of these products to ensure that it conforms with the original product as well as natural form of the product. In this study, we have focused on the characterization of the N-linked glycans and, in less details, on the O-linked glycans found on Etanercept (EnbrelTM). Using a series of methodologies, we mapped the N-linked glycosylation sites in Etanercept and also defined the types of glycan structures associated with each site. Separately, we also determined the extent of Etanercept O-glycosylation and the type of O-linked glycans.