During pathogenesis, one of the first enzymes secreted by phytopathogenic fungi are polygalacturonases (PGs). These enzymes degrade the pectin component of plant cell walls, allowing the pathogen to penetrate the plant, resulting in plant tissue maceration and necrosis. Polygalacturonase inhibiting proteins (PGIPs) inhibit the enzymatic activities of PGs by forming specific, reversible, saturable, high-affinity complexes with these fungal enzymes. Several plants have shown the presence of more than one PGIP exhibiting differential specificities towards the same fungal PG. These differential specificities are thought to be the result of the divergence of leucine-rich repeat (LRR) domains of PGIPs. The aim of this study was determine whether the inhibitory activities of Malus domestica PGIP1 (MdPGIP1) and MdPGIP2 differ due to the divergence of the LRR domains. The Mdpgip1 and Mdpgip2 genes were isolated from M. domestica cv Granny Smith. Nicotiana tabacum was transformed with each of these Mdpgip genes, separately. PGIP extracts from Mdpgip1 and Mdpgip2 transgenic tobacco indicated that there is not significant difference in the inhibitory activity of MdPGIP1 and MdPGIP2 against Botryosphaeria obtusa, Diaporthe ambigua, Verticillium dahliae, Botrytis cinerea and Fusarium verticilliodes PGs.