Pleurotus ostreatus No.42, known as the ligninolytic basidiomycetes, showed production of MnP and Lac, but did not show any LiP acitivity in static culture, grown in GPYW liquid medium. Maximum production of MnP (80U/flask) was observed on day 11 of culturing in this medium. Chromatographic purification of MnP included the use of Sepharose CL-6B and Mono-Q. The major MnP isozyme purified by column chromatography was observed to be a 36.4 KDa (single band on SDS PAGE). The 19-amino acid sequence from the N-terminal was determined by protein sequencing to be ATCADGRTTANAACCVLFP. The N-terminal sequence of the major MnP isozyme of P. ostreatus No.42 was found to be the same as a previously reported sequence of an MnP3 isozyme from this fungus.