Campylobacter jejuni is the most common cause of food-borne illness worldwide, accounting for ~225,000 infections in Australia per year. Infection is zoonotic and is associated with consumption of under-cooked or poorly prepared poultry, in which C. jejuni is a commensal. A unique molecular feature of C. jejuni is the ability to post-translationally modify membrane-associated proteins by the N-linked addition of a heptasaccharide glycan. Glycan biosynthesis is performed by proteins encoded within the pgl (protein glycosylation) locus, and attachment is mediated by the PglB oligosaccharyltransferase. Disruption of pgl genes reduces chicken colonization and adhesion to human epithelial cells, however the proteins that mediate these phenotypes, and indeed the overall function of the N-glycan, remain to be determined.  We developed mass spectrometric techniques that have allowed the identification of many novel N-linked glycoproteins in C. jejuni, and identified a non-canonical glycan that is itself modified by addition of phosphoethanolamine (pEtN) to terminal GalNAc. Quantitative proteomics and glycoproteomics have examined C. jejuni model strains NCTC11168 O (O), a clinical isolate, and NCTC11168 GS (GS), a laboratory-adapted avirulent strain derived from NCTC11168 O. Analysis of these strains demonstrated alterations in proteins responsible for the production of the N-linked glycan and its transfer. Increased Pgl proteins leads to elevated N-glycan biosynthesis and attachment, but this targets specific proteins rather than a general increase. Quantitative glycoproteomics also revealed glycopeptides that lack the typical C. jejuni glycosylation sequon (D/E-X-N-X-S/T). Recently, we have been working on the function of the N-glycosylation system, and hypothesize a role in protein stability, mediating protein complexes, and survival in diverse environments.