Incidence of listeriosis in Costa Rica or Central America has not been previously studied. The only listeriosis outbreak reported in Costa Rica was described in 1989 (Schuchat et al., 1991). Nevertheless, the Costa Rican Institute for Research and Training in Nutrition and Health (INCIENSA) has cautioned about elevated levels of L. monocytogenes in food samples (Acuña et al, 2004). In this work, we have initiated the first systematic survey of Listeria spp. distribution and diversity in Costa Rica.