Stainless steel films were reactively magnetron sputtered in argon/nitrogen gas flow onto oxidized silicon wafers using austenitic AISI 316 stainless‐steel targets. The deposited films of about 300 nm thickness were characterized by conversion electron Mö‐i;ssbauer spectroscopy, magneto‐optical Kerr‐effect, X‐ray diffraction, Rutherford backscattering spectrometry, and resonant nuclear reaction analysis. These complementary methods were used for a detailed examination of the nitriding effects for the sputtered stainless‐steel films. The formation of an amorphous and soft ferromagnetic phase in a wide range of the processing parameters was found. Further, the influence of postvacuum‐annealing was examined by perturbed angular correlation to achieve a comprehensive understanding of the nitriding process and phase formation. The amorphous phase is not very stable and crystallization can be observed at 973 K.