In this study, Electron paramagnetic resonance (EPR) spectroscopy was used to determine the gamma radiation damages in Lamotrigine and Flurbiprofen.The free radicals produced in the samples were interpreted in terms of some type of alkyl and amine radical fragments. The g values and hyperfine structure constants of the radicals were determined and the spectra were computer simulated. The free radicals were appeared to be stable at room temperature for more than two months.