Enterococcus cecorum was initially identified as a harmless commensal of the gastrointestinal tract of chickens. However, over the past 15 yr, pathogenic strains of E. cecorum have become a significant cause of morbidity and mortality in broiler breeders, and repeated outbreaks occur, but an environmental reservoir for pathogenic E. cecorum has yet to be identified. Genetic analyses of E. cecorum demonstrate that strains with increased pathogenicity are genetically related and share several putative virulence genes. Pathogenic E. cecorum carry increased antimicrobial resistance compared to commensal strains. These pathogenic strains can be recovered from retail meat and may serve as a reservoir for further spread of antimicrobial resistance among other Enterococcus spp. This review presents the current understanding of the pathogenesis of E. cecorum and briefly discusses antimicrobial resistance in E. cecorum due to the role of Enterococcus spp. in nosocomial infections in people.