The effect of light emitting diodes on direct adventitious organogenesis in Lilium regale in vitro cultures was studied. Bulb scales collected from in vitro originated bulbs were used as initial explants. The experiment was carried out on Murashige and Skoog medium enriched with 5 or 10 µM BA. Effects of red and blue light emitting diodes (LEDs) were examined individually and in combination (7 : 3). Control cultures were kept in dark or under cool white fluorescent light. Monochromic blue LEDs stimulated the formation of adventitious shoots. Blue LEDs applied alone or in combination with red LEDs increased the efficiency of adventitious bulb formation. Monochromatic red LEDs inhibited the formation of adventitious bulbs, but stimulated root formation. BA was necessary for adventitious bulbs and shoots formation, but its effect was statistically insignificant.