This study was carried out to evaluate cytotoxicity of the extracts from Sophora flavescens Ait. against L1210 (lymphocytic leukemia) and $P388D_1$ (lymphoid neoplasms) cells in vitro. We have determined cytotoxicity by MTT {3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazo-liumbromide} assay. The order of cytotoxicity of Sophora flavescens Ait. extracts against L1210 and $P388D_1$ cells in vitro is as follows: AM> EASF > CFSF > MTSF > WSF > HXSF and AM> EASF> CFSF> MTSF> HXSF> WSF. These results suggest that the ethyl acetate soluble extract of Sophora flavescens Ait may be a valuable choice for the development of antitumor agents.