extracts from young leaves of nine sweet cherry (prunus avium l.) and eight sour cherry (prunus cerasus l.) varieties, located in the germplasm collection of the 'dire？？o regional de agricultura da beira interior' (fund？o, portugal), were analysed for five isozyme systems in order to characterise these varieties and detect problems of synonymies and homonymies that frequently present. the sweet and sour cherry varieties analyzed showed low isoenzymatic polymorphism, being pgm and pgi the systems with the highest discrimination power. these systems presented seven and five different zymogrames, respectively. idh showed four patterns. skdh and 6-pgd grouped the varieties only into two patterns. the evident and discriminant restrictions of this type of analysis had got results that have only been a complement for agronomical and morphological characterization.