Doping of carbon nanotubes with nitrogen should provide more control over the nanocarbon electronic structure. In addition to the chemical and arc-discharge alternative methods used nowadays, we suggest ion irradiationas an alternative way to introduce N impurities into nanotubes. The impinging ions can directly occupy the sp < sup>2 positions in the nanotube atomic network. As an alternative way N nitrogen atoms are introduced due to the same atomic radius. In this work we studied the defects caused by exposure to N2 with various energies with the Raman spectroscopy. Kramers–Kronig analysisis determined the optical conductivityof multiwall carbon nanotudes. Electrical measurements showed that conductivity of samples increases with enhancement of irradiation of MWCNTs, clearly due to creation of more defects and N-C and irradiation-mediated doping of nanotubes is a promising way to control the nanotubes electronic structure.