A Fibrinolytic enzyme has been isolated and purified from the edible mushroom, Lepista nuda. The apparent molecular mass of purified enzyme was estimated to be 34 KDa by SDS-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of the enzyme was Tyr-Pro-Ser-Pro-Ser-His-Gln-Thr-Ala-Val-Asn-Ala-Ile-Ile-X. It has a pH optimum at 7.0~9.5, suggesting that the purified enzyme is an alkaline protease. It shows the maximum fibrinolytic activity at 55 oC. The fibrinolytic activity was inhibited by phenylmethylsulfonyl fluoride, indicating that the purified enzyme is a serine protease. The activity of the purified enzyme was totally inhibited by Hg ²⁺.