The present research was carried out to study the effect of long term chilling and freezing in year 2008 on most important grape cultivars in north of Khorasan. Two experiment were carried out. In the first experiment with regards to that Kolahdari and Kaje angoor was most important and qualitative cultivars in region for processing, fresh consuming and export, effect of natural frost on one- year, two- year and perennial branches of these cultivars in two climate conditions of Mashhad and Bojnord were evaluated. In the second experiment, one-year, two-year and perennial branches of Keshmeshi cultivar in three climate conditions of Golmakan, Qochan and Mashhad were evaluated. Factorial experiments based on completely randomized design with five replicates were used for both experiments. The traits that measured were: anatomical description of branch, re-growth, electrolyte leakage and proline content. Results from the first experiment showed that, main effect and interaction effect of genotypes and age of branches were significant for electrolyte leakage from plant cells (P≤1%). One-year and two-year branches of Kolahdari cultivar and two-year branches of Kajangoor cultivar had highest electrolyte leakage with 90.8, 89.4 and 85.6 respectively. Results of the second experiment also showed that, the main and interaction effects of branches age and sampling area on electrolyte leakage were significant. The Perennial branches from Mashhad area with mean of 65.6 had lowest electrolyte leakage. These results also showed that there is no significance difference in all significant levels between sampling areas and branches age and interaction effects of these factors. However effect of place and branches age on prolin content was significant

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