ESBL-producing organisms pose unique challenges to clinical microbiologists, clinicians, infection control professionals and antibacterial-discovery scientists. Although the prevalence of ESBLs is not known, it is clearly increasing, and in many parts of the world, 10-40% of strains of E. coli and K. pneumoniae express ESBLs (Rupp and Fey, 2003).The aim of this study was to assess the prevalence of ESBL-positive strains of E. coli and K. pneumoniae in cows with clinical signs of endometritis that were treated exclusively with Oxytetracicline for both diseases of the genital area as well as other bacterial infectious diseases.The study population included 35 Romanian Black Pied cows with clinical signs of endometritis within a farm in North Eastern of Romania. The samples were harvested using sterile cotton swabs that have been further microbiologically processed. For the phenotypic confirmation of the isolated ESBL strains, were used the combined disk test (CLSI, 2014) and the Oxoid Brilliance chromogenic ESBL Agar medium. The taxonomic classification of the isolated colonies was carried out by testing some minimal biochemical characteristics by using the MIU and TSI tests.A total of 47 bacterial strains were isolated from uterine secretions, derived from the 35 cows included in this trial. From the total of 47 isolated bacterial strains, 17 belonged to E. coli and K. pneumoniae species, from which, 6 of them were confirmed as being ESBL-positive.In this preliminary study, by phenotypic methods was confirmed a prevalence of 35.3% for the ESBL strains of E. coli and K. pneumoniae, which requires further research to confirm by molecular biology the identification of ESBL resistance genes, but also for the plasmids encoding these gene transmission.