An analytical solution of the transient temperature distribution of an electrically conducting material exposed to electromagnetic radiation is obtained. The solid material is assumed to be semi-infinite with a specified initial uniform ambient temperature. The surface is assumed to be subjected to convective heat losses. However, adiabatic surfaces boundary condition and specified surface temperature boundary condition are also treated as special cases. The effect of the applied current frequency is discussed, and the temperature rise during high-frequency electromagnetic heating, which is of particular importance in surface modification of materials, is investigated.