Gram-positive irregular rods from the genus Trueperella are opportunistic pathogens in animals, rarely causing infections in humans. Their pathogenicity is related to their adhesion properties, production of cytolysins, as well as ability to form biofilm and survive in host cells. Their pathogenesis and routes of infection are still poorly understood. In recent years, an increasing antimicrobial resistance has been noted in Trueperella spp., so the surveillance of the antimicrobial resistance of these bacteria seems to be very important. This study summarizes current knowledge about species belonging to the Trueperella genus, with a special focus on their pathogenicity and antimicrobial resistance.