Zinc tin nitride (ZnSnN2) thin films have been deposited on glass and silicon substrates using a reactive co-sputtering process. Although the deposition temperature was limited to the room temperature, the films show a highly crystallization level and a strong preferred orientation in the [001] direction. The film composition, measured using energy dispersive X-ray spectroscopy and electron probe microanalysis, indicates a possible tin understoichiometry (or a zinc and a nitrogen overstoichiometry). As confirmed by transmission electron microscopy, the main oxygen contamination of the films results from oxidation of the grains boundaries after air exposure of the samples. X-ray photoelectron spectroscopy and Mossbauer spectrometry have been used to determine the chemical environment of atoms in the ZnSnN2 crystals. Both methods confirm that Sn4+ ions are bonded to nitrogen atoms and that the oxygen contamination results in the formation of Sn2+ ions. Zinc tin nitride exhibit an electron mobility at room temperature close to 3.8 cm(2) V-1 s(-1) and an optical band gap of 1.8 eV as measured independently from UV-visible spectrometry and ellipsometry. The results obtained in the present study confirm the suitability of ZnSnN2 thin films as an Earth abundant material for absorber layer in photovoltaic devices.