ResumenSe aisló e identificó la flora bacteriana en 21 vacas donantes de embriones a partir del lavado uterino al momento de recolección de los embriones al día 7 posinseminación. La identificación bacteriana se realizó por métodos convencionales basados en las características fenotípicas, morfología, desarrollo, pruebas bioquímicas y metabólicas. Las bacterias identificadas fueron Proteus mirabilis 4.8%, Archanobacterium pyogenes 4.8%, Klebsiella ozaenae 9.5%, E. coli 14.2% Shiguella sonnei 23.8%, Bacilus spp 33.3%, Pseudomona aeruginosa 52.3% y Sthaphylococcus spp. 47.6%. En 28.6% de las vacas se identificó solo una bacteria, 52.4% dos bacterias y 19% tres o más bacterias. La alta diversidad bacteriana sugiere diversos orígenes y nuevos estudios sobre su papel individual o sinergismo en el desarrollo de la enfermedad uterina y posibles efectos sobre la respuesta superovulatoria.Palabras clave: infección uterina, bacterias, transferencia de embriones (DeCs). AbstractBacterial flora were isolated and identified in 21 embryo-donor cows from uterine washing when collecting embryos on day 7 post-insemination. Bacteria were identified by conventional methods based on phonotypical and morphological characteristics, development and biochemical and metabolic tests. The bacteria identified were Proteus mirabilis (4.8%), Archanobacterium pyogenes (4.8%), Klebsiella ozaenae (9.5%), E. coli (14.2%), Shiguella sonnei (23.8%), Bacilus spp. (33.3%), Pseudomona aeruginosa (52.3%) and Sthaphylococcus spp. (47.6%). A single bacterium was identified in 28.6% of the cows, two bacteria in 52.4% of the cows and three or more bacteria in 19% of them. The high bacterial diversity suggested various origins; new studies into their individual role and/or synergism regarding the development of uterine disease and possible effects on superovulatory response are needed.