Isoenzymes were used to examine genetic variability within and among populations of chestnut (Castanea sativa Mill.) and wild cherry (Prunus avium L.). Isoenzymes were sufficiently robust to allow the attribution of chestnut shoots to stumps; other markers were required to confirm the estimations of wild cherry clone sizes. No genetic structure was observed within populations of the two species and no significant departures from Hardy-Weinberg equilibrium were detected for the isoenzymes tested excluding one locus. F-statistics and measurements of genetic distances revealed little genetic differentiation among populations of these species. This could be explained by the influence of human activities and the limited number of generations observed for these species since the last glaciation.