Maggot fibrolase (MsMg-1) was purified from the maggots of Mimela splendems using ammonium sulfate fractionation, DEAE Affi-gel affinity chromatography. This protease had a molecular weight of 85 kDa as determined by SDS-polyacrylarnide gel electrophoresis under reducing conditions. It showed strong proteolytic and fibrinolytic activities. The purified enzyme was strongly inhibited by phenylmethanesulfonyl fluoride, Mn²⁺, and Zn²⁺ but it was not by EDTA, EGT, Mg²⁺, Ca²⁺, and Li²⁺ ions. In these experimental results, we have speculated that MsMg-1 is a serine protease with a strong fibrinolytic activity.