In this paper, the preparation and magnetic characterization of single-phase epitaxial α″-Fe16N2 thin films along with the effect of addition of some alloying elements on the saturation magnetization (Ms) of the films deposited by dc magnetron sputtering on single crystal Si(1 0 0) substrates have been described. Apart from the other deposition conditions, the epitaxy of α″-Fe16N2 thin films is strongly dependent on nitrogen partial pressure as its variation causes to develop other iron nitride phases like γ′-Fe4N and Fe3N. Single-phase epitaxial α″-Fe16N2 film is found to have maximum Ms value of 1800 ± 20 emu/cc. The effect of Co, Pt, and Cr additions on the Ms value of α″-Fe16N2 thin films has also been investigated.