The aim of the present study was to examine the effect of heat shock for triploidy induction on oxidative stress and immunity indicators of the Caspian Salmon ( Salmo trutta caspius ) during the early development stages (fertilized egg, eyed egg, hatching and active swimming).In this study, 6 female broodstock and 9 male broodstock were used.The gametes of each sex breeders were pooled together to eliminate individual effects. For triploidy induction, temperature shock was applied 40 minutes after fertilization at 26 °C for 10 minutes. The eggs belonged to heat shock treatment and the diploid (control) treatment incubated under natural conditions at 10-12 °C and cultured for up to 84 days after fertilization. The results showed that polyploidy induction rate was 81% in trypoloid treatment in active swimming stage, which was measured through the dimensions of red blood cells. To ensure the accuracy of triploid induction, flow cytometry method was used and the triploidy was proven. The primary and final weight of the diploid larvae were significantly higher than those of the heat shock group, while the weight gain percentage was not significantly different between the diploid larvae and heat shock group. Sampling was performed 3 hours, 32 days and 45 days after fertilization for fertilized egg, eyed egg and hatched egg, respectively, for active swimming larvae sampling was performed in 64 days post fertilization. All samples collected in 3 replication for each treatment. The results showed that activity of antioxidant enzymes Super Oxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPX) in the beginning of embryo development in diploid and heat shock treatments were low, but in the later stages of life, the activity of these enzymes increased. The levels of SOD, CAT and GPX enzymes change at fertilized egg, eyed egg and hatching stages in the heat shock treatment were significantly higher than the diploid treatment. In diploid and heat shock treatments, increased levels of Malondialdehyde (MDA) were obsereved which related to start of active feeding. Also, high levels of MDA were observed in heat shock treatment in stages of fertilized, eyed and hatching egg in comparison to diploid treatment. In present study, the level of immunity variables in different stages of embryonic development was significantly different between the two treatments. The levels of Immunoglobulin (IgM) were higher in stages of fertilized egg and eyed egg, total protein in stages of fertilized egg and hatching and globulin in stages of eyed egg and active swimming, respectively, in heat shock treatment. The concentrations of lysozyme, complementarity alternate (ACH 50 ), albumin, immunoglobulin (IgM), total protein and globulin factors in heat shock treatment were similar or higher than these of in diploid treatment, which indicates that the fish immune system was not disrupted because of triploidy induction. Keywords : Oxidative stress, immunity, Triploid, Caspian Sea salmon, Embryo development