Electrical wiring of different types of pyranose oxidase (P20) (fungal wild type, recombinant wild type with a hexahistidine tag, mutant form E542K with a hexa-histidine tag) from Trametes multicolor, and recombinant P20 from Coriolus sp. overexpressed in Escherichia coli as well as of pyranose dehydrogenase (PDH) from Agaricus meleagris and Agaricus xanthoderma with an osmium redox polymer (poly(1-vinylimidazole)(12)-[Os(4,4'-dimethyl-2,2'-dipyridyl)(2)Cl2+/+) on graphite electrodes was carried out. After optimization studies using glucose as substrate, the biosensors, which showed the best characteristics in terms of linear range, detection limit and sensitivity were selected, viz. wild type P20 from T multicolor and PDH from A. meleagris. These two enzymes were used and investigated for their selectivity for a number of different sugars.