The object of this study was to investigate the effects of oral administration of Isoprinosine (163.3mg/ kg) for 21 days, in rabbit before vaccination with (RHVD) vaccine on cellular and humoral immune response. Forty rabbits were divided into four equal groups. 1^st group was left without treatment and used as control, 2^nd group was treated with oral dose of isoprinosine (163.3 mg/kg) for 21 days, 3^rd group was vaccinated with rabbit haemorrhagic viral disease (RHVD) vaccine and the 4^th group was orally administered with isoprinosine (163.3 mg/kg) for 21 days then was vaccinated with (RHVD) vaccine. Results proved that vaccinated treated rabbits showed a significant improvement in phagocytic percent, phagocytic index, lysozyme activity, nitric oxide, serum total protein, serum albumin, gamma globulins in comparison with vaccinated non-treated rabbits. DNA destruction percent observed in liver and kidney tissue samples of treated, vaccinated and treated vaccinated groups. In conclusion, it appears that isoprinosine improves the cellular immune response in vaccinated rabbits and it has a genotoxic effect on hepatocytes of vaccinated rabbits.