Abstract At relatively low temperatures (room temperature and 200 °C) nitrogen was introduced into an iron layer underneath a top layer of nickel. This was done by implanting the nitrogen into the Ni layer. It was observed that subsequently part of the N diffuses into the Fe layer. The concentration depth profiles of N in the Ni/Fe bilayers were recorded with the nuclear reaction analysis technique using the 15N(p,α) 12C reaction at E p = 1.02 MeV. From these depth profiles, measured as a function of implantation dose, implantation temperature and anneal temperature, it was suggested that nitrides are formed in iron. To our knowledge, nitride formation has not been reported before at such low temperatures in the absence of radiation damage.