Ni-Mo alloy coatings containing more than 49 wt% Mo have been electrodeposited onto mild steel from ammonia-citrate solution in the presence of two kind of imidazolium-based ionic liquids as additive. Pulse plating technique was employed for electrodeposition. The structural components of the coatings were evaluated employing X-ray diffraction method (XRD). Microstructure, morphology and chemical composition of the coatings were investigated using scanning electron microscopy (SEM) and X-ray energy-dispersive spectroscopy (EDX) analysis. SEM micrographs revealed different morphology of Ni-Mo electrodeposits in the presence of ionic liquids. Also XRD patterns illustrated that present conditions lead to deposit Ni-Mo coatings with amorphous/nanocrystalline structure. The results showed that, within the range of 30-35 wt% Mo nanocrystalline Ni-Mo with the lowest grains size have been developed. Temperature and pH were varied to investigate their effects on deposited Ni-Mo film characteristics. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.065208jes]