This study was conducted to evaluate the effects of supplementation of different dietary electrolyte balance (DEB, as the equation of Na+K-Cl milliequivalents (meq) /kg of dry matter) levels on physiological responses and metabolic rate of rams exposed to heat stress and to determine which DEB level is the optimum. A total of 20 Farafra mature rams were used in this trail. These animals were divided into Four equal homogenized groups (5 each) as control (received basal diet only and its DEB was 98 meq/kg of feed DM), T1: DEB 200 meq/kg DM, T2: DEB 300 meq/kg DM and T3: DEB 400 meq/kg DM. Different DEB content of the three treatments was achieved by adding sodium bicarbonate by a rate of 0.74%, 1.48% and 2.22% of kg DM in T1, T2 and T3, respectively. Thermal response parameters, blood constituents, and respiratory activities were determined during the experimental period before (11-12 am) solar exposure and after 3 hours of solar exposure (3-4 pm). The results revealed that supplementation of different DEB levels reduced rectal and skin temperatures and respiration rate before and after solar exposure. However, gas volume per minute (GV) and tidal volume (TV) increased significantly in all treated groups. Volume of oxygen consumption (VO2) and metabolic rate tended to increase by treatment. Also, serum DEB level (Na+K-Cl) increased significantly in all treatments. In conclusion, supplementation of different DEB levels had beneficial effects on the thermal responses, respiratory activities and gas exchange parameters of heat exposed rams and the optimum DEB level is 300 meq/kg of DM.