In this project Co 2 Fe 1-x Cr X Al Heusler alloys have been prepared by mechanical alloying (MA). Final Fm3m phase was obtained after 15 hours of milling. The analysis of X-ray data confirms the existence of the CoAl phase in the samples obtained after one hour of MA. With the increased Fe content, the reduction in peak intensity over time is not as rapid. This phenomenon can be related to the catalytic effects of Cr. for all of the samples, M s is less than the estimated Slater Pauling value. The deviation of the magnetic moment per formula unit from the theoretical Slater Pauling value decreases with the increasing Fe content, which is attributed to a very low moment at the Cr sites. Also the effect of annealing and mechanical properties of these compounds was studied. Then four Heusler compounds (Co 2 FeGe, Co 2 FeSi, Fe 2 CoGe, Fe 2 CoSi) were prepared with the same method and effect of vacuum annealing on properties was studied. According to the structural measurements 15 hours milling was enough for crystallization of these compounds. During annealing the crystallite size increased and lattice ordering enhanced. Two super lattice peaks was appeared in X-ray spectrum due to enhancement of lattice ordering of two Si content compounds. In Co based compounds the saturation magnetization value increased to a closer value of Slater Pauling model because of improvement of lattice ordering. The value of Ms in some Fe based compounds was higher than Slater Pauling prediction. The magnetic structure of these samples was analyzed by mosbauer spectroscopy and the atomic moments were determined. At the end 6 compounds of 24 valence electron Heusler alloys were prepared. Investigation of properties of ball milled Mn 3-x Ga samples showed that the stoichiometry of these compounds will change during milling process so all of these 24 valence electron samples were prepared by arc melting. Fe 2 TiGe and Fe 2 TiSi were no single phase. 5 samples of Mn 3 Ga were prepared. The difference between these samples was the annealing temperature and the ball milling process after arc melting. The ball milled and annealed samples had L1 0 and DO 22 structures respectively. The saturation magnetization deviated from Slater Pauling value in annealed samples. The annealed samples showed a coercive field in range of 0.7T. The X-ray measurements showed that a little Mn is exsolved at the two higher annealing temperatures. One of these samples had a 4 times higher magnetization and same coercivety in comparison with previous works. Cr 2 CoGa sample had L2 1 structure but magnetization deviated from Slater Pauling value. In contrast Cr 2 FeGe had a tetragonal structure. The magnetic structure of this sample was studied by mosbauer spectroscopy measured at 20 and 300K and a change in magnetic structure was detected by temperature. Magnetization of Fe 2 VGa was too low. This value was explained with a weak itinerant ferromagnet state. Keywords: Heusler alloys, magnetic structure, mechanical alloying, itinerant ferromagnet