The effect of periodic vacancies to the magnetism of the Fe monolayer was investigated by calculating the electronic structures using the full-potential linearized augmented plane wave method within the GGA approximation. We considered four types of vacancies, point defect, I type, + type, and H type which are consisted of one, three, five and seven vacant sites, respectively. We found that the Fe atoms nearest to the vacancy have the largest magnetic moment in each system, and the value of magnetic moment of the atom was increased as the number of vacancy site is increased. The value of the largest magnetic moment in the systems of point defect, I type, + type, and H type are 3.08, 3.09, 3.15, and 3.30 bohr magnetons, respectively.