In this study, some important immune parameters in the unfertilized and fertilized eggs, larvae of 10 days post hatching (DPH), juveniles of 1 to 12 month post fertilization (MPF) and the female broodstock were evaluated. In the Persian sturgeon, there was a significant decrement in the lysozyme activity from the unfertilized eggs to the 10 DPH larvae and after that, the remarkable variations were not observed. The C3 concentration did not show any significant variations from the unfertilized eggs to the 1 MPF and after that, it significantly decreased. Apart from the fertilized eggs, the variations of the IgM level were similar to the C3 level in the early life stages of the Persian sturgeon. In the Sterlet, the lysozyme level was decreased significantly from the unfertilized eggs to 10 DPH larvae, then it was increased in 1 MPF and finally, a significant difference was not observed from 2 to 12 MPF. The variations of both the IgM and the C3 levels were similar from the fertilized eggs to 12 MPF. In conclusion, the considerable fluctuations of the immune parameters were observed in early life stages especially under 1 MPF which indicates immunologically sensitivity of the fish in these stages.