In summary, we report on a novel approach to obtain hydrogels by chemical crosslinking of unfunctionalized hydrophilic PEtOx using polyperoxides of different chemical composition by simple heating of the mixed powders. The influence of temperature, time and concentration as well as chemical composition of the polyperoxide on the crosslinking process and the properties of the resulting hydrogels have been investigated. Furthermore, we found that the swelling temperature has an impact on the degree of swelling and the stability of the obtained hydrogels. The crosslinking degree increases with temperature and concentration of polyperoxide. Rheological measurements confirm that the PEtOx/polyperoxide based hydrogels are rather soft materials with storage moduli of a few kPa. We also demonstrated that the chemical composition of polyperoxide crosslinker does have a minor effect on mechanical properties of the resulting hydrogels. Comparison of SEM on freeze-dried samples and samples observed by cryo-SEM confirmed the significant impact of sample preparation on the sample morphology. The latter suggests double-pore structure, which should be investigated in more detail. The present approach of using polyperoxide crosslinker is particularly simple and should be applicable to a wide range of hydrophilic polymers without the need of any functionalization or modification and may be useful for different applications.