The species of Leuconostoc are uncommon opportunistic pathogens, which can be isolated in critically ill patients, immunocompromised hosts and in nosocomial infections. They are mostly isolated in bacteremia associated to intravascular devices and to the use of total parenteral nutrition. Nevertheless, other infections due to Leuconostoc sp have been described among which, meningitis, bloodstream infections, urinary tract infections and peritonitis have been reported. In this article we describe a series of cancer patients with Leuconostoc sp infections and their associated clinical conditions, and a literature review is presented.