Ferromagnetic resonance measurements at the X-band were taken at room temperature mainly to investigate the mechanical properties of Ni films 180 nm thick prepared on both pure and SiO2-covered Si(100) substrates at 190 degrees C by biased d.c. plasma sputter deposition at 2.5 kV in Ar gas. A negative bias voltage V-s between 0 V and -80 V was applied to the substrates during deposition. The homogeneous intrinsic stress sigma(i) induced in the films is compressive (sigma(i) < 0). The magnitude of sigma(i) depends on V-s. For the Ni/SiO2 system -sigma(i); has a maximum as V-s reaches about -30 V because the impurities are most strongly embedded in the film with incoming Ar particles. When -V-s is over 30 V the more energetic Ar particles contribute to a decrease in -sigma(i), through resputtering the impurities. For the Ni/Si system -sigma(i) only increases monotonically with V-s, mainly owing to the peening effect. The anisotropic planar stress sigma(u) which is much smaller in magnitude than sigma(i) is also induced in the film for both systems. The origin of sigma(u) is not understood at present. Thus, the g-factor varies with V-s,mainly in agreement with the dependence of sigma(i) on V-s for both systems.