Background: Staphylococcus lugdunensis is Gram-positive cocci of the staphylococcaceae family. S. lugdunensis despite having a clotting factor (wall coagulase), was classified in the coagulase negative staphylococcus group (CoNS) for lack of free coagulase. Although this bacterium is part of the human normal flora, in terms of virulence, S. lugdunensis is in second place after S. aureus. S. lugdunensis causes a wide range of cardiovascular, bone and joint infections, blood infections, skin and soft tissue infections, central nervous system infections, and urinary tract infections. This bacterium cannot produce S. aureus toxins, but it has various pathogenic factors such as delta hemolysin, lugdulysin, atlL autolysin, lysozyme resistance, MSCRAMM adhesins, ica opron, iron opron and ability to produce SCV colonies. These factors may explain the same pathogenic potential as S. aureus in S. lugdunensis. Fortunately, unlike other members of the Staphylococcaceae family S. lugdunensis has highly sensitive to most antibiotics and responds well to treatment. In the last decades, the rate of isolation of S. lugdunensis as a pathogen worldwide is increasing, but unfortunately, because most Iranian laboratories do not have a specific CoNS species identification on the laboratories agenda, these species were reported as CoNS or contamination. Therefore, no information is available on the prevalence and pathogenicity of this bacterium in Iran.