Auricularia auricula-judae has long been used as food and traditional remedies in Asian countries such as Korea and China. In this study, we evaluated the in vitro anti-tumor activity of various fractions from the ethanol extracts of Auricularia auricula-judae using various tumor cell lines. To do this, the mesh of Auricularia auricula-judae was mixed with 70% ethanol and heated at 1000C for 6 hrs and ethanol extract (ETOH) was collected. Ethanol extract was fractionated with dichloromethane (DCM), ethyl acetate, n-butanol and a water extract at room temperature as well as concentrated in a vacuum concentrator at a controlled temperature(<500C). The P388D1 macrophage and Sarcoma 180, human NSCLC NCI H358 (bronchioalveolar) and SNU1 cells (Gastric carcinoma) were cultured in RPMI. As the results, the cytotoxicity of the fractional extracts decreased significantly (P<0.05) in a dose-dependent manner. Dichloromethane extract (1 mg/ml) was the highest (P<0.05) in all experimental cell lines. There was also a significantly different sensitivity (P<0.05) among the P388D1, Sarcoma 180, NCI H358 and SNU1 cells for the fractional extracts. According to IC50 values, the most potent cytotoxic activity of dichloromethane fraction was found in Sarcoma 180 and NCI H358 cell lines. Butanol fraction appeared more cytotoxic to SNU1 cell line and water fraction had the highest cytotoxicity in P388D1 cell line. We did not find any significant difference between MTT and SRB assays in their ability to estimate cytotoxicity in all cell lines. Our findings suggest a potent antitumor activity of various fractions from the ethanol extracts of Auricularia auricula-judae depending on the solvent fractions and tumor cell lines. Further in vitro and in vivo studies will provide more information on the active compounds responsible for these activities and their potential as an anti-cancer remedy.