Fullerene is a hollowmolecule of carbon atoms and may accommodate guest atoms inside it. Therefore a number of Na atoms may be doped inside it. We have used the model potential calculations to investigate the stability and charge transfer when Na atoms are doped inside C84 and C60. In our calculations, the number of the Na atoms doped inside fullerene varies from 1 to 9 in case of C84 and 1 to 6 in case of C60. The binding between Na atoms has been modeled using Gupta potential and Coulomb Potential. The interaction between Na atoms and fullerene molecule is modeled using exp potential and Coulomb Potential. The Minimization of total cohesive energy w.r.t to charge transfer and size of the cluster results in total charge transfer fromsodiumatomcluster in each energetically favorable case however different values of on shell coulomb repulsion V restricts the number of sodium atoms which can be doped inside fullerene molecule For all clusters, charge transfer is energetically favorable.