ryophytes have been used as medicinal plants for more than 400 years in China, Europe and North America.There is also evidence confirming the antibiotic and anticancer activity of Bryophytes against, prokaryotes, fungi anddifferent cancer cells. The purpose of the current study was to investigate cytotoxic property of Homalotheciumsericeum (hedw.) schimp., which is a bryophyte, extracts on rat glioma (C6) cells for 48 hrs, in vitro. We first collectedtwo different (acetone and A) extracts from H. sericeum by two different extraction processes. C6 cells were seeded in96 well plates (2x104cells/well) and incubated for 24 hrs. Following this incubation period, the medium was replacedwith only medium (control) or medium with extracts at concentrations of 0.17, 1.7, 17, 85 or 170 µg/mL for 48 hrs.Cytotoxicity was determined by using 3-(4,5-dimethylthiazol-2yl)- 2,5-diphenyltetrazolium bromide (MTT)colorimetric assay. Acetone extract of H. sericeum at 0.17, 1.7 and 17 µg/mL concentrations did not change the survivalrate of C6, but 85 and 170 µg/mL inhibited about 16 % and 36 % after 48 hr (p<0.001), respectively. Extract A atconcentration of 0.17 µg/mL did not also affect C6 viability, but 1.7, 17 (p<0.01), 85 and 170 (p<0.001) µg/mLdecreased C6 cell viability by 6, 8, 24 and 33 % for 48 hr, respectively. Acetone and A extracts of H. sericeum showeda moderate but similar dose dependent cytotoxicity on C6. Further studies are needed to clarify the content of theseextracts.