For the assessment of irradiation influence on 2-(piperidin-1-ylmethyl)phenol single crystals (C12H17NO), electron paramagnetic resonance measurements were carried out on the samples exposed to 60Co radiation at dose values of 22.8, 45.6 and 68.4 kGy at room temperature. Electron paramagnetic resonance signals were not observed in non-irradiated sample and in samples irradiated at dose values of 22.8 and 45.6 kGy. The electron paramagnetic resonance measurements were performed on the single crystals. This irradiated single crystal was rotated in steps of 10°. One type of radical center was found. The average values of g and hyperfine constant of the detected radiation damage center were calculated from experimental spectra as follows: g = 2:0052, AH = 0:74 mT.