The effect of organic selenium (OR-Se) based on Selenomethionine produced by Saccharomyces cerevisiae (Alkosel® NCYC R397) on the growth performance, carcass traits, blood hematological and biochemical indices and antioxidant status of growing rabbits under high ambient temperature. In an 8-week experimental period, a total of 48 New Zealand White rabbits were randomly distributed into 4 groups. Animals were allotted into 4 groups: control (basal diet) and T1, T2, T3 that were fed the basal diet supplemented with 0.4, 0.8 and 1.2 mg OR-Se/kg diet, respectively. Results showed that stressed rabbits in OR-Se-supplemented groups had a significant improvement (p<0.01) in growth parameters (except feed intake), dressing percentage and abdominal fat. In addition that, the supplemented groups (T2, T3) recorded higher levels (p<0.05) in red blood cells, hemoglobin, and packed cell volume. And these groups had a notable increase (p<0.05) in serum total protein and globulin and a decline in total cholesterol and triglycerides. In connection supplemented OR-Se statistically (p<0.01) increased serum total antioxidant capacity and declined Malondialdehyde compared with the control. Our findings of this study concluded that the supplementation of growing rabbit diets with OR-Se under hot times can alleviate the adverse effects of heat stress by improvement of the antioxidant status that reflected on growth performance, carcass characteristics and blood parameters.