Luminescence of Ce3+ in the hydrogen peroxide induced sulfuric acid solutions was observed to be quenched by Ce4+ ions in the solution by energy transfer due to electric dipole interaction between Ce3+ and Ce4+. A systematic investigation of the energy transfer characteristics of Ce3+-Ce4+ mixture has been made by measuring the absorption, luminescence and excitation spectra at room temperature. The effect of the concentration of Ce3+ on the energy transfer process has been also studied and the critical transfer distance (Ro) has been calculated considering Förster type interaction between the ions and found to be 8.7 A for the mixture of 1 x 10(-4) mol 1(-1) Ce3+ and 3 x 10(-4) mol l(-1) Ce4+.