Yeasts with counts of above 106 g−1 wet weight and high diversity were found in the fecal pellets of rodents and marsupials from a mosaic of forest fragments, grasslands, cultivated fields and pasture in Rio de Janeiro. The most frequently isolated yeasts were Debaryomyces hamsenii, Pichia membranaefaciens and Issatchenkia orientalis (and its anamorph Candida krusei), probably reflecting a high fruit content in the diet of these animals. The opportunistic pathogens Candida albicans, Candida glabrata and Candida tropicalis were isolated at lower frequency. Some Pichia anomala and P. membranaefaciens cultures had killer activity affecting many of the other isolates. These animals can be involved in dispersal of yeasts.