Restrictions patterns of the ITS rDNA and a partial fragment of the β-tubulin gene were shown to help identify Phaeoacremonium species associated with diseased grapevines. PCR-RFLP markers revealed a high frequency of P. parasiticum, together with P. aleophilum, in fungi isolated from stems and trunks of mature diseased vines showing ‘hoja de malvón’ disease, and from young declining plants in Argentina. This distribution is different from that in vineyards in other parts of the world, where P. aleophilum is dominant. Indeed, this is the first report associating P. parasiticum with diseased vines.