Peach powdery mildew )Podosphaera pannosa (is one of the most important and common diseases in peach orchards grown in many areas in Iran. In order to evaluate the different varieties of peach reaction against powdery mildew, experiments were conducted in randomized complete block design with three replications in 2014-2016. The research was conducted in two conditions of natural infection and artificial inoculation in the collections of Agriculture and Natural Resources Research Station in Meshginshahr. Treatments included 25 varieties of peaches Robin, Redheaven, Early red, Spring crest, Vesevio, Redtop, J.H. Hale, Shasta, Early glo, Amesdn, Loring, Spring time, Velvet, Sudanel, sundans, Anjiri, Haj Kazemi, Paeizeh, Elberta, Baby gold 7, Dixired, Red skin, Sabz-e- Mashhad, Sun crest and July Elberta. The evaluation on different varieties of peach reaction to the causal agent powdery mildew was done using Ivascu and Buciumanu as follow: 0: Immune, 1: Very resistant 2: Resistant 3: Medium resistant 4: sensitive, 5: Very sensitive. The results of 3-year evaluation showed that there were significant differences between the degrees of resistance against the studied disease among the treatments. Comparison of means by Duncan test showed that the treatments Early glo, J.H. Hale, Red haven, Anjiri, Loring and Red top were selected as very resistant and July Elberta, Vesevio, Elberta, Spring crest, Velvet, Shasta, Early red and Redskin as resistant cultivars, Baby gold 7, Sundans, Amesdn, Haj Kazemi, Spring time, Dixired and Red skin selected as Medium Resistant, Sudanel and Sun crest were sensitive varieties and Sabz-e- Mashhad and Paeizeh were very sensitive varieties to causal agent of peach powdery mildew. The results showed that the effect of year and interaction between cultivar and year on pollution in terms of both natural and artificial powdery mildew was not significant.