We have compared the site-by-siteN-glycosylation status of human lactoferrin (Lf) produced in maize, a monocotyle-don, and in tobacco, usedas amodel tobacco plants were stably transformed and recombinant Lf was purified from both seeds and leaves. N-glycopeptides were generated by trypsin digestion of recombinant Lf and purified by reverse-phase HPLC. The N-glycosylation pat-tern of each site was determined by mass spectrometry. Our results indicated that the N-glycosylation patterns of recombinant Lf produced in maize and tobacco share common structural features