Abstract: To investigate the phylogeny of Pleurotus calyptratus, both the nuclear ribosomal DNA large subunit (nrDNA-LSU) and the internal transcribed spacer regions (ITS) were sequenced. The analysis results show that P. calyptratus has no close affinity with Tectella but with Pleurotus, and that the pleurotoid basidiomata and veil are not homologous characteristics to Tectella. The close relationships of P. calyptratus with P. djamor other than the veiled species, P. dryinus and P. levis, are also revealed by the present molecular phylogenetic analyses.