The viscosity coefficient of gaseous nitrogen was measured with a vibrating-wire viscometer of very high precision. The measurements were performed along the six isotherms of (298.15, 323.15, 348.15, 373.15, 398.15, and 423.15) K and at pressures up to a maximum of 35 MPa. The gas densities needed for the evaluation of the measuring values were calculated using an equation of state by Span et al. (J. Phys. Chem. Ref. Data 2000, 29, 1361-1433). The reproducibility is +/- 0.05 %, whereas the total uncertainty is estimated to be +/- (0.2 to 0.3) %. The viscosity values of the isotherms were evaluated with a power series expansion in terms of reduced density. A comparison with the most recent correlation by Lemmon and Jacobsen (Int. J. Thermophys. 2004, 25, 21-69) shows that the new values agree in the temperature and density ranges of the measurements within +/- 0.7 %. Based on a comparison with the most reliable data from the literature, it is concluded that the new values are appropriate to improve the viscosity surface correlation of nitrogen.