"> Coagulase negative Staphylococci are the most prevalent cause of bovine subclinical mastitis. The current study were designed to study their occurrence, antibiogram and their ability to form biofilms. A total number of 95 CNS isolates were recovered from 400 lactating. S. xylosus (36.84%), S. chromogenes (12.63%), S. epidermidis (10.53%), S. saprophyticus (8.42%), S. haemolyticus (7.38%) were the most common recovered species. Disk diffusion method against 14 antimicrobials discs was used to detect their antibiogram. 100% were sensitive to Imipenem, 96.84% were sensitive to Enrofloxacin, 85.26% to Chlramphenicol and 84.21% to Vancomycin. But, 95.79% were resistant to Ampicillin, 77.9% resistant to Cefoxitin, 35.8% resistant to Cefuroxime, 32.63% resistant to Amoxycillin and 18.95% resistant to Clindamycin. Cultivation on Congo Red Agar (CRA) was carried out to detect biofilm formation. 47.37% were positive and S. epidermidis was the most biofilm positive species on CRA by the percentage of 70%. Haemolysins were studied by cultivating CNS on sheep blood
agar. 25.26% were β-haemolytic, 71.57% (n=68) were γ-
haemolytic and 3.15% were α- haemolytic.