Broiler is one of the most common sources of poultry meat which has become one of the most popular and fastest poultry production in the world. The performance of broilers is directly affected by increasing or decreasing temperature and heat & cold Stress. In this study, it has been attempted to evaluate the cooling and heating degree-days (HDD and CDD) at different broiler breeding periods for Khorasan Razavi province. For this purpose, monthly mean temperature data for the statistical period (1988-1998) derived from 13 synoptic stations of the province were used. The cooling and heating degree-days were calculated for each of the breeding weeks based on specific thresholds and their spatial distribution was assessed. In the next step, the relationship between the cooling and heating degree-days and geographical parameters were evaluated. The results showed that with increasing latitude, the cooling degree-days decreased and the heating degree- days increased. The northern and western regions of the province have shown greater heating requirements in all broiler breeding periods, while the cooling requirements at different stages of broiler breeding have been higher for the eastern and southern regions of the province. In terms of total cooling and heating requirements, the northeast, southwest and western regions of the province; the cities of Khaf, Gonabad, Kashmar, Sarakhs and Sabzwar have the least heating-cooling requirements in the six-week broiler breeding period and are considered suitable climates for the development of this economic activity.