Cat bite infections are one of the most common infectious diseases presenting to veterinary practices and to emergency rooms at human hospitals. This review describes the disease in humans and cats, the origin of organisms involved in cat bite abscesses and the importance of selected organisms such as members of the genus Porphyromonas in the disease. It also discusses future directions, the importance of identifying significant organisms and why an understanding of antimicrobial susceptibility patterns is of consequence to the outcome of the disease in humans and cats.