In-silico virtual screening of bacterial surface enzyme Staphylococcus aureus Sortase A against commercial compound libraries using FlexX software package has led to the identification of novel inhibitors. Inhibition of enzyme catalytic activity was determined by monitoring the steady state cleavage of a model peptide substrate. Preliminary structure activity relationship studies on the lead compound resulted in the identification of compounds with improved activity. The most active compound has an IC50 value of 58 μM against the enzyme. © 2007 Elsevier Ltd. All rights reserved.