Gases emerging from Fe-Zr-N films with various compositions during heating were analyzed by thermal desorption spectroscopy. Their structures and magnetic properties were also investigated. H₂, N₂ and Ar were detected at 300∼400°C, 500°C and 650°C, respectively. Higher amounts of N₂ were detected from films which contained higher amounts of N₂. The composition of films changed because of emergent N₂ is as follows. The composition changed from N/Zr > 1 to N/Zr∼1, but was unchanged in the case of N/Zr ≤ 1. (100) preferred orientation occurred in films in which composition was N∼Zr > 8 (at%) at as-made while (110) or random orientation occurred in the case outside of that. In the former conditions, Fe-Zr-N films showed excellent soft magnetic properties and thermal stability up to 700°C.