Tryparedoxin peroxidase (TXNPx) is an essential constituent of the main enzymatic scavenger system for reactive oxygen species (ROS) in trypanosomatids. Genetic studies have demonstrated the importance of this system for the development and virulence of these parasites, representing a potential target for the discovery of new trypanocidal drugs. In this work, the mitochondrial TXNPx fromLeishmania braziliensiswas cloned, overexpressed, purified and crystallized. The crystals diffracted to 3.3 Å resolution and belonged to space groupP4₂2₁2, with unit-cell parametersa=b= 131.8,c= 44.4 Å. These studies will contribute to a better understanding of the molecular mechanisms involved in ROS detoxification by trypanosomatids.