Mating system and genetic variability were studied in a southern and a northern population ofPicea abies, in Czechoslovakia and Finland. Both populations had considerable genetic variability, with expected heterozygosities of 0.17 and 0.23, respectively, at nine loci. The two distant populations were more differentiated (Gst=0.12) than has been found in studies on ScandinavianPicea abies.Both populations had a considerable degree of partial selfing, with estimates of outcrossing of 0.83 and 0.74 in the populations from Czechoslovakia and Finland, respectively.