We have grown, for the first time, Mn-doped epitaxial beta-FeSi2 films on a Si(001) substrate by reactive deposition epitaxy (RDE) method, in which Fe and Mn atoms were co-deposited on hot substrates. These films became flatter after annealing at 850 degrees C for 30 min in ultrahigh vacuum. The lattice constant of a-axis, the resistivity and energy gap of the Mn-doped epitaxial beta-FeSi2 films, decreased with increasing the evaporated Mn to Fe ratio as observed in sintered beta-FeSi2.