Determining the exact nature of N-glycosylation in Caenorhabditis elegans, a nematode worm and genetic model organism, has proved to have been an unexpected challenge in recent years; a wide range of modifications of its N-linked oligosaccharides have been proposed on the basis of structural and genomic analysis. Particularly mass spectrometric studies by a number of groups, as well as the characterisation of recombinant enzymes, have highlighted those aspects of N-glycosylation that are conserved in animals, those which are seemingly unique to this species and those which are shared with parasitic nematodes. These data, of importance for therapeutic developments, are reviewed.