Nanocrystalline and nano-/amorphous Mg 1 . 9 M 0 . 1 Ni (M=Ti, Zr, V) alloys were synthesized by mechanical alloying (MA) as well as by MA followed by annealing. The ball milling and heat treatment conditions for obtaining amorphous or nanocrystalline alloys were optimised for different alloy compositions. The phase composition, microstructure and morphology of the as-milled and heat-treated powders were determined by XRD, TEM and SEM. Thermal stability, crystallization and grain growth processes in the nano-/amorphous alloys were investigated, too. After milling the alloys have hexagonal Mg 2 Ni crystal structure. The crystallites size of the milled as well as of the milled and then annealed alloys was estimated to be in the range of 10-20 nm. The grain size increases slightly during heating to above 700 K. Hydrogen sorption kinetics and storage capacity of the as milled nano-/amorphous Mg 1 . 9 M 0 . 1 Ni alloys were characterized as well.