A hemolytic fraction has been obtained from fresh tubers of Momordica cochinchinensis. The fraction was strongly adsorbed on DEAE-Sepharose CL6B. It did not stain with Coomassie brilliant blue in SDS-polyacrylamide gel electrophoresis and it gave no immunoprecipitin arcs in immunoelectrophoresis. The hemolytic activity of the fraction was resistant to heat and proteolytic enzymes. The behavior of the fraction in thin-layer chromatography and its positive reaction in Liebermann-Burchard test indicated that the hemolytic activity of the fraction can be attributed to a steryl glycoside(s).