Abstract: We present an investigation of titanium nitride samples obtained by additive technologies using EPR-spectroscopy. It was established that the main type of defects in this material is nitrogen atoms with unpaired electrons (N-radicals). It was found that the defect concentration increases by two times under illumination. This effect is reversible which is evidenced by the charge exchange of the N-centers. The data obtained may be useful for producing coatings based on the investigated samples.