Red and yellow AlGaInP/GaAs light-emitting diodes (LEDs) with multiple quantum wells grown by the metalorganic chemical vapor deposition technique were irradiated at room temperature by 10 MeV electrons at fluences of 10 12 -10 16 cm À2 . The damage constants of the minority carrier lifetime and the light-output reach the values of (1-2.5) Â 10 À14 cm 2 at room temperature measurements. At the same time, the radiation tolerance of these diodes increases up to 50 times when the temperature is lowered down to 16 K. The beneficial effect of the Mg doping of the p-GaP(Mg) window layer on the LEDs radiation tolerance at a high forward current density has been demonstrated. status solidi physica a AlGaInP Light-Emitting Diodes www.pss-a.com