Beta-cryptoxanthin (b-Cr) is a pro-vitamin A and one of the major carotenoids that can be commonly found in mammalian serum and tissues. Foods rich in certain fatty acids are known to be effective to gain a healthy immune system. In the present study, we evaluated the effect of b-Cr on rabbit humoral and cellular immune responses to have a better vision about the mechanism of effect of carotenoids on immune system. Twenty rabbits were randomly divided into five groups (4 per group): Groups consisted of: 1) control group (normal saline; 2) b-Cr (control); 3) vaccine control; 4) 5 mg/kg b-Cr o.p. + vaccine; 5) 10 mg/kg b-Cr o.p. + vaccine. Blood samples were obtained from the marginal ear artery at three time points: days 0, 14 and 21 of the study. Blood CD4+ and CD8+ lymphocytes and Serum Immunoglobulin and Cytokines content were evaluated. Results show that b-Cr administration increased the blood CD4+ lymphocytes count (P > 0.01). Serum IgG, IgM and IgA levels increased (P > 0.05) following b-Cr administration. b-Cr treatment increased serum IL-4 levels (P > 0.05). According to presented results, b-Cr may increase the humoral immunity in mammals. So, it would possible has a potentially beneficial effect on health and on prevention of the immunity related diseases.