In this paper the conservation of different bacteria, yeasts and molds from diagnostic material was examined with a commercial deep freeze system. 137 bacteria isolated from the stomachs of dogs, cats and pigs and from duodenal juice of cats and 7 isolates of yeasts and fungi from diagnostic material were conserved with the deep freeze system MICROBANK-TM (Mast Diagnostica). Furthermore 62 Helicobacter pylori-isolates and 1 Helicobacter felis-isolate were conserved with this system. After a storage period of 24 hours up to 20 months the isolates were recultured. 96% of the conserved microorganisms could be grown. It was not possible to cultivate 1 fungus-isolate (Fusarium sp.). 2 Helicobacter pylori-isolates, spiral bacteria from the stomach of a pig and a Clostridium tyrobutyricum-isolate were only recultured after 24 hours, 1 isolate Moraxella sp. after 2 months and another 4 anaerobe isolates after 5 months. The system MICROBANK-TM proved to be suitable for conservation and was also efficient for the conservation of microorganisms, which could not easily be cultivated.