Biodosimetry is focused on effects of ionizing radiation at cellular and molecular levels of living organisms so that a qualified retrospective estimate of radiation load can be made. Two biodosimetry methods were evaluated in irradiated piglets: complete blood count analysis and quantification of chromosomal aberrations in lymphocytes using a micronucleus test. Animals were whole-body irradiated with gamma radiation at doses of 0-10 Gy. The analysis of complete blood count was performed at intervals ranging from 0 to 48 hours. Micronuclei were measured at 4 hours after irradiation. Changes in lymphocyte counts and increased levels of micronuclei reflected received dose of ionizing radiation.