we proposed to quantify the intensity of the immune response to the heberbiovac-hb vaccine in offsprings of normal rats and with iugr. two treatment schemes were used, a group at 0-5-10 days, and another at 0-11-22 days. seven days after the last dose, blood was extracted and the antibody titer was quantified in each offspring. the results showed that 100 % of the offsprings vaccinated with the scheme 0-11-22 seroconversed compared with 87.5 % in the scheme 0-5-10. it was also proved that that the control group of the scheme 0-11-22 attained a higher percent of animals in the category of hyperresponders. it was concluded that the immune response in both groups have sufficient intensity to rise antibody titers, and that the offsprings under the scheme 0-11-22 respond with more intensity than those of the scheme 0-5-10.