We present first-principles calculations on Fe, Nd, and SmCo5 using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method. The magnetic moments of Fe, Nd and SmCo5 were calculated using the WIEN2K code. The moments for BCC Fe and HCP Nd are 2.27µB and 2.65µB respectively in good agreement with experimental values. The calculated magnetic moment and magneto-crystalline anisotropy are in good agreement with experimental values. The spin-density maps in the (001) plane shows that the effect of the spin–orbit coupling on the spin-density structure of Sm atoms is stronger than that of Coulomb correlation. We also study the influence of the magnetization.