Variation of 9 isozyme systems was studied in Polish populations of 3 species of the genus Anthoxanthum: the native A. odoratum s. str. L. and A. alpinum Á. Löve & D. Löve, as well as the alien A. aristatum Boiss. Results of this study show that A. odoratum is characterized by a high isozyme variability of lowland populations, weakly correlated with habitat type, and partial genetic distinctness of montane populations. Moreover, 5 isozyme markers have been identified (Pgi-2, Dia-2, Mdh, Idh, Pgm) for the allopolyploid A. odoratum. Populations of A. aristatum are highly polymorphic (P = 98%). The observed isozyme differentiation of its populations (FST = 0.087