In the 19th century the barren Karst regions were reforested with non-native European black pine (Pinus nigra Arnold), whose oldest stands are nowadays already degrading. In the bottom layer native broadleaved tree species are occurring again among which is also the European nettle tree (Celtis australis L.). All properties of the European nettle tree indicate its suitability for the input in the Karst forests from the ecological and economic site of view. Unfortunately the certified seedlings in the Slovenian area are not available so it seems reasonable to consider the possibility of successful generative propagation and production of quality seedlings. For this reason the experiment in which the success of generative propagation of European nettle tree was examinated. The comparison was made between two different times of seeds harvest, two different times of sowing the seeds and two different places for sowing the seeds. Furthermore the comparison between different type of seeds pre-treatment was made. The most effective method has proven to be outside autumn sowing with 93 % germination. The outside spring sowing after cold stratification had slightly lower but still satisfactory germination (77,8 %). Quite different results were obtained with inside sowing where the average germination was only 1,6 %. Additional processing of seeds has proved to be unnecessary as the variously treated seeds showed no significant differences in germination. As the results showed no significant differences in germination between seeds, harvested in September and those, harvested in October, the early harvesting in September or as soon as seeds become black-purple coloured, is advisable.