In this paper, the preparation and magnetic characterization of single-phase epitaxial alpha ''-Fe16N2 thin films along with the effect of addition of some alloying elements on the saturation magnetization (M-s) of the films deposited by dc magnetron sputtering on single crystal Si(100) substrates have been described. Apart from the other deposition conditions, the epitaxy of alpha ''-Fe16N2 thin films is strongly dependent on nitrogen partial pressure as its variation causes to develop other iron nitride phases like gamma'-Fe4N and Fe3N. Single-phase epitaxial alpha ''-Fe16N2 film is found to have maximum M-s value of 1800 +/- 20 emu/cc. The effect of Co, Pt, and Cr additions on the M-s value of alpha ''-Fe16N2 thin films has also been investigated. (C) 2009 Elsevier B.V. All rights reserved.