This work aims to isolate the 28KDa proteinase from the parasite Fasciola hepatica (Linnaeus, 1758). This cysteinyl protease was purified by classical methods such as the ammonium sulphate precipitation, G-25 and G-75 gel filtration chromatographies, affinity chromatography with thiol sepharose 4B and SDS-PAGE 12% electrophoresis. The enzymatic activity of Cathepsin L was monitored in each step of purification using a specific substrate. The cysteine proteinase was observed as a pure and homogenous band in the SDS-PAGE gel. The recovery percentage was 12.7%, with a specific activity of 337,500 umol, min-1 mg-1 and a purification factor of the enzyme of 260. Using this simple scheme of purification we purified to homogeneity the cathepsin L of 28KDa from the regurgitate in an effective way compared with other alternative methods. The amount of protein obtained was 0.032 mg·mL-¹. The enz...