DFT calculations of the molecular structure of the intrazeolite eta(1){CuNO}(11) adduct and the N-14 and O-17 hyperfine and Cu-63 superhyperfine coupling constants were performed and compared with previous EPR results. The calculations confirmed the choice of signs adopted in the previous analysis of the experimental data and the character of the SOMO. The influence of the basis set and the exchange-correlation functional on the HFCC and the spin-density distribution was investigated and briefly discussed. The global repartition of the spin density over Cu (rho = 0.11), N(rho = 0.58), and 0 (rho = 0.34) atoms determined from the Mulliken population analysis compared well with the experiment. The N-14 hyperfine tensor was successfully reproduced with the LanL2DZ basis and BPW91 functional, whereas in the case of the Cu-63 superhyperfine dipolar tensor T the agreement, except for that of the T-zz component, was less satisfactory because of an overestimated polarization of the 3d(yz) orbital, regardless of the computation level. For the calculation of a(iso) (Cu), because LanL2DZ treats inner electrons with the effective core potential, a 6-311G(df) basis set appeared to be the most appropriate, leading to excellent agreement between the experimental and calculated values.