The transglutaminases (TGase; EC2.3.2.13) (R-glutaminyl-peptide-aminase-gamma-glutamyltransferase) are a family of enzymes that catalyse post-translational modifications in proteins, producing covalent amide bonds between a primary amine group in a polyamine or lysine (amine donor), and a gamma-carboxamide group of the glutamyl residue of some proteins(amine receptor). These enzymes were detected for the first time in animals, where they modify structural proteins, and are widely distributed in bacteria, animals, and plants. Of all the reactions that are catalysed by TGases, protein crosslinking has probably attracted the greatest interest owing the industrial applications of these catalytic reactions. A review of the patents related to the different cloned TGases and its putative applications in medicine, food processing, and other applications as polymer obtaining, etc., is presented here. Due to the widespread number of recently published patents about this enzyme, a classification in relation to a) species origin and b) application field, is presented.