A system and a method for the production of recombinant N-glycosylated target proteins. The system comprises a prokaryotic organism (e.g. Escherichia coli) into which is introduced a genetic information encoding for a metabolic apparatus capable of carrying out the requested N-glycosylation of the target protein. Said prokaryotic organism also contains the genetic information required for the expression of one or more recombinant target proteins. The metabolic apparatus preferably comprises specific glycosyltransferases for the assembly of the oligosaccharide on a lipid carrier and an OTase that covalently links this oligosaccharide to specific residues of the desired protein.