We have implanted boron ions into films of Fe‐Ni alloy composition. A homogeneous distribution of boron was determined from the sputter Auger analysis with a concentration of 18% and 34% for low‐ and high‐dose implantation, respectively. The resistivity of film was increased by a factor of 2 and 4 as a result of low‐ and high‐dose implantation, respectively. The magnetic properties of these films are studied as a function of annealing temperature by using FMR measurements. Both the uniaxial anisotropy field and FMR linewidth are dramatically decreased as a result of annealing at elevated temperatures. The changes of effective magnetization of these films are strongly dependent on implanted boron concentration.