Polyurethane foams using oligoetherols synthesized from 1,3-bis(2-hydroxyethyl)uracil, boric acid and ethylene carbonate are obtained. Some properties of the foams, such as apparent density, water uptake, dimensions stability, thermal stability, compression strength, thermal conductivity, oxygen index and horizontal burning were investigated. The obtained foams show an improved thermal stability and reduced flammability. Кеуwords-1,3-pyrimidine ring, 1,3-bis(2-hydroxyethyl)uracil, boric acid, ethylene carbonate, oligoetherols, polyurethane foams, improved thermal stability, reduced flammability.