NMR spectroscopy was applied for the precise determination of the C-13 nuclear magnetic dipole moment on the basis of new results available for nuclear magnetic shielding in methane and helium-3. For this purpose small amounts of (CH4)-C-13 and He-3 as the solutes were observed in CO2 or Xe as the gaseous solvents by C-13, He-3 and H-1 NMR spectra at the constant external field, B-0 = 12.7586 T. In every case the measured resonance frequencies (v(C), v(He) and v(H)) were linearly dependent on the density of solvent. It allowed us the evaluation of the above frequencies free from intermolecular interactions after the extrapolation of experimental points to zero-density of gaseous solvents. Combining these measurements with the relevant value of C-13 shielding in methane it was possible to determine the C-13 nuclear magnetic moment with much better precision than before, mu(C-13) = 0.70236944(68)mu(N). Application of new theoretical results for carbon shielding in the methane molecule permitted similar evaluation of the C-13 nuclear magnetic moment, it shows that the experimental and theoretical results are consistent and the new C-13 magnetic moment can be efficiently applied in the field of NMR spectroscopy. (C) 2011 Elsevier B. V. All rights reserved.