Crown and root rot is the most important almond disease in Chahar Mahal va Bakhtiari province. Phytophthora cactorum was found to be a major causal agent of almond decline in the province. Reaction of crown and root to P.cactorum on one-year-old plants of 10 genotypes and 12 cultivars of Prunus dulcis and one genotype of Amygdalus orientalis from Chahar Mahal va Bakhtiari province were investigated under greenhouse conditions (at 26±8 0C). Six months after inoculation, plants were removed from pots and certain characters such as rate of plant mortality, root weight, pathogen progress and crown and root colonization were recorded. The results indicated that A.oerintalis had the plant highest mortality and lesion size and the lowest root weight. Therefore we could say Talkheh Sadeghabad and A.oerintalis were the most resistance and susceptible rootstocks to P.cactorum respectively.