Mycocepurus is a Neotropical genus of fungus-growing ants (tribe Attini) in the subfamily Myrmicinae. The genus is known from Mexico, south to Brazil and Argentina. Like other attines, they primarily grow fungi of the tribe Leucocoprini (family Agaricaceae). They use many different substrates for growing their fungi, from dry leaves and caterpillar dung to fruit matter. One of its species, Mycocepurus smithii, which lives in South America, reproduces by cloning – all ants in a colony are clones of the queen. M. castrator is a parasite of M. goeldii.