More than one thousand rodent remains have been found in three different lacustrine sediment beds of Miocene age at Bełchatów (Poland) - an opencast brown coal mine. Three fossil assemblaged (Bełchatów C - the oldest, Bełchatów B and Bełchatów A) contain abundant rodent remains (mainly teeth) and correspond to biostratigraphic zone MN 4/5, MN 5/6 and MN 8/9, respectively. Aboud 80% of the rodent material was found in the uppermost layer (Bełchatów A). The remaining two assemblages, of not dissimilar ages and with similar Orleanian/ Astaracian faunas, countain 11% (Bełchatów B) and 9% (Bełchatów C) of the material studied. Most species (except for the relatively numerous Sciuridae and Castoridae and one dipodid tooth) have already been described. However, recent studies on cricetids and eomyids have led to a revision of the previously proposed ages of Bełchatów C and Bełchatów A.