A fibrinolytic enzyme has been isolated from the edible honey mushroom, Armillariella mellea and purified. The apparent molecular mass of purified enzyme was estimated to be 19800Da by SDS polyacryl amide gel electrophoresis and 19900Da by gel filtration, indicating that it was a monomer. The enzyme was optimal at pH 7, suggesting that the purified enzyme was a neutral proteinase. It shows the maximum fibrinolytic activity at $55^{circ}C$, is completely inactivated above $65^{circ}C$, and still indicates 40% of activity at $37^{circ}C$. The fibrinolytic activity has been decreased by the addition of EDTA. Fifteen amino acid sequence was determined by protein sequencing techniques.