The radiolytic formation of Ag nanoparticles in crosslinked PVA hydrogel was investigated. The reduction of Ag+ ions was performed using strongly reducing species such as hydrated electrons, propan-2-ol and PVA radicals. Ag+ ions were efficiently reduced in swollen PVA matrix by PVA radicals. Thermal and thermooxidative properties of radiolytically obtained nanocomposites were affected by the content of nanofiller as well as by different routes of preparation.