DNA gyrase is a type II topoisomerase that is essential for chromosome segregation and cell division owing to its ability to modify the topological form of bacterial DNA. In this study, the C-terminal domain of the GyrA subunit of DNA gyrase from Staphylococcus aureus Mu50 strain was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.80 Å resolution using a synchrotron-radiation source. The crystal belonged to space group P2(1), with unit-cell parameters a = 37.28, b = 80.19, c = 50.22 Å, β = 110.64°. The asymmetric unit contained one molecule, with a corresponding V(M) of 2.02 Å(3) Da(-1) and a solvent content of 39.2%.