The American Type Culture Collection, which is also known as the ATCC, is a not-for-profit bioscience organization that maintains the world's largest and most diverse collection of microbiological life. Many laboratories and institutions maintain their own stockpile of microorganisms, usually those that are in frequent use in the facility. Some large culture collections are housed and maintained, usually by universities or private enterprises. But none of these rivals the ATCC in terms of size.

The ATCC collection includes repositories of bacterial species, animal viruses, cell lines (which are important for the growth of certain types of viruses), fungi, plant viruses,