Chagas´s disease, first diagnosed in the early 20^th century, is annualy responsable for thousands of deaths worldwide. Even being such a public heath dilema, no efficient treatment or cure has been developed. Studies based on the mechanisms of  T. cruzi´s cell death could be a potencial targeting area for the development of a rational and effective treatment. Considering this, the purpose of this project was to compare phosphatase activities, which are involved in apoptosis' signaling cascade, in two T. cruzi strains (Y and Tulahuen 2) with different resistance to oxidative stress.  Studies in our laboratory have shown that Tulahuen 2 cells are more resistant to the oxidative stress generated by hydrogen peroxide. Phosphatase activity was determined by using pNPP as substrate. Using different extract protein concentrations and reaction time, it was observed a seven-fold higher phosphatase activity in the Tulahuen strain when compared to the other one. The enzymes were also characterized in relation to optimum pH and substrate specificty.  Tulahuen 2 had an expressive acid phosphatase activity (optimum pH at 4.0), however in the presence of Mg²⁺ (10 mM) enzyme activity was higher and had a broad range (pH 5-8).  Y strain showed the same activity profile in the presence or absence of  Mg²⁺, but phosphatase activity was higher in the presence of this cation. The results reemphasized the heterogenicity between T. cruzi strains and potentially stablishes a relationship between resistance to oxidative stress and phosphatase activities.