The aim of this study was to check for prevalent pathogens all over South Korean dairy farms using PCR diagnostic tool (STARTCHECK®) which was provided by HIPRA and also to show that STARTCHECK® can be used to complement Somatic Cell Count (SCC) and bacteria! culture to monitor mastitis at a herd level1 by detecting the major mastitis causative agents (Staphylococcus aureus, Escherichia coli, Coagulase Negative Staphylococci (CNS) and coliform bacteria.