To investigate antitumor components of Korean higher fungi, the carpophores of Ganoderma lucidum (Fr.)Karst. were collected at Gal-mae-ri in Gyeong-gi Province and extracted with 0.1N sodium hydroxide solution. The extract was purified by dialyzing through Visking tube and a dark brownish power was obtained. The antitumor activity of the fraction was tested against sarcoma 180 implanted in mice. The tumor inhibition ratio of the fraction against the tumor was 87.6% in doses of 50 mg/kg/day for the period of ten days. The tumor in five of 15 mice was completely regressed. The antitumor fraction was chemically analyzed and found to be a complex of polysaccharide and protein, from which four monosaccharides and eighteen amino acids were identified.