Apicidin is a cyclic tetrapeptide lcyclo-(N-O-Methyl-L-Trp-L-Ile-D-Pip-L-2-anuno-8-oxo-decanoyl)] isolated from Fusarium pallidoroseum by bioassay guided separation. It is a potent inhibitor of apicomplexan histor~ deacetylase (IC50 1-2 riM), a broad spectrum antiparasitic agent in vitro against apicomplexan parasites and has shown in vivo efficacy against Plasmodium berghei malaria. Isolation, structure and stereochemistry are discussed.