| The present study characterized the distribution; biofilm formation ability of common SCCmec(staphylococcalcassette chromosomemec) types of CoNS isolates from hospitalized patients (HP) and health-care workers(HCW) in northwest of Iran. Thirteen species of CoNS were identified by using of the conventional micro-biological tests includedS.epidermidis,S.haemolyticus,S.hominis S.warneri S.auricularis S.saprophyticus,S.lugdunensis,S.caprae,S.scheliferi,S.xylosus,S.capitis,S.simulansandS.cohnii. High prevalence of methicillin-resistant (MR-CoNS) isolates (76.2%) was observed. The prevalence of biofilm-producing isolates was higher inHP (93%) than HCW (82.5%). There was not a significant statistically difference between the presence oficaA,icaDandaapgenes in these groups (p-value˃0.05). However, a significant statistically difference was observedin the presence ofIS256between two groups (p-value˂ 0.05). No significant association was observed betweenany SCCmectype and biofilm formation or the presence of biofilm related genes. The high prevalence of MR-CoNS and consequently, MDR isolates, as well as, their high ability to form slime or biofilm, is a commonconcern in our hospitals. Biofilm formation ability or the p |