In this study, cytotoxicity, apoptotic and necrotic effects of Agaricus sylvaticus Schaeff were investigated. The tissue fragments from taken dry basidiocarps were developed by tissue culture method in malt extract agar. Primer and secondary mycelium were obtained by incubation at 27 °C, darkness for 10 days, respectively. Three pellets were taken from the secondary mycelium and its development completed in 7 days at 140 rpm at 27 °C in nutrient broth. The samples were prepared for cytotoxite, apoptotic and necrotic studies by extracting in 80 °C, 70% ethyl alcohol for 1 hour in a soxlet device. In cytotoxicity studies, sample extract concentrations were applied to MCF-7 and L929 fibroblast cells as 0.5 mg / ml, 0.25 mg / ml, 0.125 mg / ml, 0.0625 mg / ml and 0.03125 mg / ml. The WST-1 solution was added and the absorbance was measured in a microplate reader at a wavelength of 440 nm as a result of the incubation. Apoptosis and necrosis were detected in the same cell line as the double staining experiment. Binary staining solution was prepared and MCF-7 and L929 Fibroblast cells were applied at the same concentrations. At the end of the incubation, measurements were done at 20X magnification in a fluorescence microscope with FITC and DAPI filter. Toxite varies depending on concentrations. At dose 0.125mg/ml, in MCF-7 cancer lines showed 5% cytotoxicity. Cell viability was increased in fibroblast cell lines at all different doses given. Low-grade apoptosis and necrosis have been observed.