Superoxide dismutases (SODs) are metalloenzymes that promote the dismutation of the cytotoxic radical O₂^- into H₂O₂ and O₂. SODs together with catalases have strong anti-oxidant properties and have been shown to protect normal cells as well as a number of pathogens from intracellularly-generated and phagocyte-generated reactive oxygen species. This has led to the proposal that SODs may represent an alternative molecular drug target for chemotherapeutic agents against pathological parasites such as Trypanosoma brucei, responsible for sleeping sickness in Africa. This is supported by recent experiments in Leishmania which demonstrate a significantly reduced survival rate in macrophages of SOD-deficient parasites expressing SOD antisense RNA. The gene for the FeSOD of Trypanosoma brucei (TbFeSOD) was cloned into the expression vector pET28a. The 6xHis-tagged protein was immobilized on the affinity resin Ni²⁺-NTA superflow (Qiagen), eluted with 0.1M Tris/HCl, pH 8.5 containing 100mM imidazole, cleaved with thrombin, and concentrated with a centriprep concentrator to 8.0 mg/mL. The crystallization conditions were screened by the hanging drop vapour diffusion method by using sparse-matrix kits: the classic suite and the PEG’s suite (Nextal) at 18^oC. TbFeSOD crystals were obtained in 30% PEG 4000, 0.2M MgCl₂ at pH 8.5 and X-ray data were collected to 2.0 Å resolution using an in-house rotating anode X-ray generator coupled to a Mar345 image plate detector. Data processing was performed with the program DENZO.  The crystals belong to space group P2₁ with cell parameters a=68.3Å, b=76.5Å, c=77.0, β=92.7^o.  The structure was solved by molecular replacement using the homologous SOD from T. cruzi as the search model.