In this study, Pleurotus ostreatus Jacq. ex. Fr., which are collected from Gaziantep and its culture form that are sold in stores are used as material. Antimicrobial activity of ethanol extract of P. ostreatus is determined by agar dilution method. Also, mineral composition of P. ostreatus are determined in atomic absorption spectrometry by wet digestion method. The aim of the study is to detect and compare both mineral content and antimicrobial activity of natural and cultural forms of P. ostreatus. In the studies, the fungus has been shown to have low antimicrobial activity. It is said to be higher than the natural form of mineral metal levels.