Radiation defects induced by ion bombardment of multicomponent oxide glasses of five compositions (phosphates and borosilicates) were investigated by means of electron paramagnetic resonance (EPR). The samples were implanted with N +, O +, Ar +, Mn +, Cu + and Pb + ions at energy E=150 keV at three different doses between 3×10 15 and 10 17 ions/cm 2. The broad anisotropic EPR spectra with principal g-values answering the relationship g z > g y > g x ~ g e ( g e is g-factor of free electron) were observed for the samples of all five compositions. The g-values depend on glass composition. For example, g z ranges from 2.016 to 2.057. Computer simulation shows that the spectra of many samples are superpositions of two spectra with g-values answering the mentioned relationship. These spectra are attributed to molecular O 2 − ions weakly coupled with glass network. In some samples narrow almost symmetric lines with g=2.0025±0.0005 were observed. The possible radiation defects responsible for this signal are discussed.