Fungi of the genus Pleurotus were shown to produce the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor mevinolin. Crude methanol extracts and the purified inhibitor from three different species, P. sapidus, P. saca and P. ostreatus, were tested using the solubilized microsomal HMGCoA reductase from Chinese hamster ovary cells. The identity of the inhibitor was also confirmed by thin layer chromatography, high pressure liquid chromatography and mass spectroscopy.