Helicases are ubiquitous enzymes, which utilize the energy liberated during nucleotide triphosphate hydrolysis to separate double-stranded nucleic acids into single strands. These enzymes are very attractive targets for the development of new antibacterial compounds. The PcrA DNA helicase from Staphylococcus aureus is a good candidate for drug discovery. This enzyme is unique in the genome of S. aureus and essential for this bacterium. Furthermore, it has recently been published that it is possible to identify inhibitors of DNA helicases such as PcrA. In this report, we study the properties of recombinant PcrA from S. aureus purified from Escherichia coli to develop ATPase and helicase assays to screen for inhibitors.