Since the report made by Veselago in 1968 about materials with negative refractivernindex, and strictly speaking since the experimental realization in 2000 by R. Shelby, et.rnal. of artificially constructed materials exhibiting negative index, many investigatorsrnand scholars became interested and devote their time and knowledge in search ofrnthese negative index (NI) materials, either from artificially engineered materials or tornderive them from naturally occurring materials.rnThis thesis is devoted to the analysis of the electrodynamics and the dispersionrnproperties of magnetized plasma with ferromagnetic grains (MPFG) in a constantrnmagnetic field. A magnetized plasma naturally is not transparent to light for somernrange of frequency. This range of frequency which the magnetized plasma is not transparent,rnobviously, is a range in which the permittivity is negative. So, if, in some way,rnwe introduce magnetically active materials into the magnetized plasma in such a wayrnto enhance its magnetic activity we may achieve a magnetic resonance, a dispersionrnrelated with magnetic response of magnetized grains to the variable magnetic field.rnThe mathematical analysis and the different graphs against the frequency of the wavernshow that in a relatively narrow frequency band !M (!M is the ferromagnetic resonancernfrequency) both the magnetic permeability and the electric permittivity havernnegative value and the MPFG behaves as a NI material. That is, the introductionrnof the ferrite grains makes the magnetized plasma transparent to the electromagneticrnwave for the range of frequency where the ordinary plasma is nontransparent. Moreover,rnin this range of frequency the phase and group velocity of the electromagneticrnwave are opposite, which is one of the criterion for the left-handed media