A phylogenetic analysis of more than 350 multicopper oxidases (MCOs) from fungi, insects, plants, and bacteria provided the basis for a refined classification of this enzyme family into laccasessensu stricto (basidiomyc-etous and ascomycetous), insect laccases, fungal pigment MCOs, fungal ferroxidases, ascorbate oxidases, plant laccase-like MCOs, and bilirubin oxidases.