We have investigated the stability of several types of porous silicon light-emitting devices (LEDs). It shows that simple blue-emitting devices have an average life of about 0.5 h. When the samples are oxidized in a solution of hydrogen peroxide, electroluminescence IEL) can be stabilized for more than 7 h. After the peroxide treatment the red photoluminescence of the samples is also stable for several hours. The best method to stabilize the blue EL is to evaporate a thin layer of 50% indium/50% tin onto the porous silicon. Parallel to the increase of quantum efficiency by two orders of magnitude (P. Steiner et al., Jpn. J. Appl. Phys., 33 (1994) 6075), continuous light emission for 80 h is possible in this way. More stable than the blue devices are red/infrared-emitting porous silicon samples, LEDs of this type have been operated for about 100 h.