A protein-polysaccharide fraction was isolated from the mycelial culture of a Korean basidiomycetous fungus, Hebeloma crustuliniforme, and was named HCA (Hebeloma crustulineforme fraction A). When intraperitoneally injected at 200 mg/kg/day once daily for 10 days, HCA inhibited the growth of sarcoma 180 solid tumor in ICR mice by 65.1% (p＜0.05). HCA also exerted protective effect against leukopenia induced by cyclophosphamide with the protection ratio of 39.7% (p＜0.01).