Cold stress is one of the most important abiotic stresses that affects growth and performance in crops and forages. Increases in winter temperatures may negatively influence winter survival by stopping maximal cold acclimation previous to freezing temperatures. Therefore, research is needed to identify resistant genotypes and strategies that may help advance cold acclimation and increase freezing tolerance. The purpose of this research was to evaluate over-wintering in different genotypes of tall fescue (24 early genotypes, 24 late genotypes selected from poly-cross hybrids and 24 parental genotypes) under both drought stress and non-stress conditionsGenotypes in the three groups were studied as a combined analysis according to a randomized completely block design. Drought stress was applied during the growing season and all of the genotypes were under natural cold stress and similar irrigation in the winter. Traits were studied in three stages in October, January and April. The results of October data showed that drought stress significantly affected dry matter yield and proline content. Also drought stress decreased dry matter yield and increased proline content. The results of February data showed that drought stress significantly affected traits. The results of April data indicated that drought stress had a significant impact on dry matter yield. The results showed that drought stress before winter resulted in an improvement in freezing tolerance for tall fescue, however it had no signi?cant effect on over wintering index. Also there was no significant difference between the genotypic groups for dry matter yield of October and April for over-wintering index. However, there was significant differences between genotypes for these traits reflecting that there was high differences for these traits in genotypes. Keywords : Festuca, over wintering, cold and stress