Aim: This study was aimed to identify of catalase negative Gram positive cocci (CNGP) isolated from milk samples of dairy cows with subclinical mastitis and to determine susceptibility of microorganisms to antibiotics.

Materials and Method: Totally, 104 CNGP cocci were isolated from dairy cows with subclinical mastitis. Isolates were selected according to coloni morphological and haemolysis properties and were identified by VITEC 2.

Results: Out of isolates, 32 (30.76%) were identified as Enterococcus faecalis, 21 (20.19%) Aerococcus viridans, 18 (17.30%) E. faecium, 13 (12.50%) Streptococcus agalactiae, 11 (10.57%) S. uberis, 3 (2.88%) Lactococcus garviae/lactis ssp. lactis, 2 (1.92%) L. lactis ssp. latis and 1 (0.96%) L. garviae. Three isolates (2.88%) could not be identified. The susceptibilities of CNGP cocci were determined to be different to antimicrobial agents.

Conclusion: This study shown that identification of CNGP cocci isolated from dairy cows with subclinical mastitis should be performed accordingly.