Thermal radiation effects on unsteady flow past an oscillating semi-infinite isothermal vertical plate with uniform mass flux have been studied. The fluid considered here is a gray, absorbing-emitting radiation but non-scattering medium. The dimensionless governing equations are solved by an efficient, more accurate, and unconditionally stable and fast converging implicit scheme. The effect of velocity and temperature for different parameters like thermal radiation, Schmidt number, thermal Grashof number and mass Grashof number are studied. It is observed that the velocity decreases in the presence of thermal radiation.