The goal of this research was lipid peroxidation process assessment for different levels of ultrahigh frequency electromagnetic field and different time exposure. There were animal 171 MHz one time exposures during 1 and 3 hours. In the blood serum of exposed animals the malondialdehyde concentration evaluated the lipid peroxidation process. The research results shown the statistically significant electromagnetic field biological effects as for maximum field strength 1 hour exposure, as lower field strength 3 hours exposure.