Glycosylation of recombinant proteins is of particular importance because it can play significant roles in the clinical properties of the glycoprotein, such as enzyme activity, protein stability, pharmacokinetics, and immunogenicity. In this work, the N-glycan structures of recombinant human Factor IX (tg-FIX) and Protein C (tg-PC) produced in the transgenic pig mammary gland were determined. It has been found that the majority of N- glycans of tg-FIX and tg-PC are complex bi- and tri- antennary with one or two terminal N- acetylneuraminic acid moieties. There were significant species-specific and tissue/cell- specific differences in N-glycan structures among animals used for transgenic animal bioreactors. N- glycan profiles of tg-FIX were consistent during lactation with respect to the overall distribution of sialylated vs. neutral oligosaccharides. The results show that the porcine mammary gland can be a viable candidate bioreactor for production of recombinant human glycoproteins that require complex, sialylated N-linked glycans.