FeNi films were deposited by DC magnetron sputtering at different Ar pressures. The structure and magnetic properties of the FeNi films are affected by the Ar pressure. Ferromagnetic resonance (FMR) measurements were done at a frequency of about 8.85 GHz. Both the value of resonance field and resonance line width show strong dependence on the Ar pressure: the lowest value of the resonance field and the narrowest resonance width correspond to the smallest argon pressure. Increase of the Ar pressure causes the films to have a significant perpendicular anisotropy with the easy axis pointing out of the plane. The magnetic properties and FMR were also studied for the [FeNi(170 nm)/Ti]n/FeNi(170 nm) (n = 1, 2, 5) structures prepared at the smallest Ar pressure. The FMR studies showed that the obtained multilayers are very robust: the value of the resonance field and resonance line width of the [FeNi/Ti]n/FeNi multilayers are very close to the corresponding values for the FeNi films.