Northern and western border of pygmy field mouse Apodemus uralensis population area passes through southern Poland. First sites of the species have been discovered in the '50 of the 20th century. Since then, a total of 79 sites has been found. Latest research revise data concerning the occurrence borders of pygmy field mouse. Three out of four newly found stations are located in the western part of the country, north-west from the hitherto known sites of the species.