Abstract The study contains data from 3302 preys found in Barn owl pellets from 15 sites within the Provinces of Foggia and Bari (Apulia, Southern Italy). Eleven micromammal species were identified. Microtus savii and Apodemus sylvaticus were the most frequents preys. No specimen of Clethrionomys glareolus and Apodemus flavicollis were found which is probably due to the habitat typology examined (all thermoxerophilous phytocoenosis). The Sorensen Index showed a high faunistic affinity among all the sites studied and other localities of Apulia. However, by applying the index of biocenotic differences (Renkonen) a difference in some localities, in relation to Microtus savii and Insectivores abundance, was found.