The magnetic state of alpha-Fe particles and the behaviour of nitrogen and zirconium during annealing in Fe96N4 and Fe85.6Zr7.6N6.8 magnetic thin films have been studied by conversion electron Mossbauer spectroscopy for Fe-57. The crystalline phases present in the Fe-N annealed films were alpha-Fe and gamma’-Fe4N, and those in the Fe-Zr-N annealed films were alpha-Fe and ZrN. In the Fe-N films annealed below 300 degrees C, about 60% nitrogen is incorporated interstitially into alpha-Fe and the rest is used for the formation of gamma’-Fe4N. In the Fe-N film annealed at 500 degrees C, almost all nitrogen participates in the formation of gamma-Fe4N, leading to the grain growth of alpha-Fe particles and an increase in coercive force. The values (291-325 kOe) of internal magnetic field of iron sites in alpha-Fe in the Fe-Zr-N films are much smaller than that (333 kOe) of the iron site in pure alpha-Fe. Even if the Fe-Zr-N films were annealed at 500-700 degrees C, some zirconium and nitrogen is still incorporated substitutionally and interstitially into alpha-Fe, respectively. In particular, the substitutional zirconium depresses the grain growth of alpha-Fe particles, perhaps due to a chemical interaction between zirconium and iron.