We investigated the surface electronic structure and magnetism of the NiAs structured MnAs(0001) and MnSb(0001) using first-principles full-potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation. We considered the Mn- and anion(As or Sb)-terminated surfaces for both the MnAs(0001) and MnSb(0001) systems. The calculated magnetic moments of the surface Mn atoms for Mn-terminated MnAs(0001) and MnSb(0001) systems are much enhanced to have 3.79 mu(B) and 4.04 mu(B), respectively, compared to the corresponding center layer values, 3.10 mu(B) and 3.32 mu(B). The anion atoms in the Mn- and anion-terminated systems have negative magnetic moments with the values between -0.09 mu(B) and -0.18 mu(B). The effects of surface termination and the band hybridization on the magnetism and the electronic structure are discussed with the calculated density of states.