Heat and mass transfer effects on unsteady free convection flow past a linearly accelerated isothermal vertical plate with variable temperature and mass diffusion in the presence of thermal radiation have been studied. The fluid considered here is gray, absorbing/emitting radiation but a non-scattering medium. At time t′ > 0, the plate is accelerated with a velocity u = u 0t′. And at the same time, the plate temperature is raised linearly with time t and also the mass is diffused from the plate linearly with respect to time. The dimensionless governing equations are tackled by the Laplace transform method. The velocity, temperature, concentration, the rate of heat transfer and the rate of mass transfer are studied for different physical parameters like thermal Grashof number (Gr), mass Grashof number (Gm), Schmidt number (Sc), Prandtl number (Pr), radiation parameter (R) and time (t) graphically. © 2012 Pushpa Publishing House.