Non governmental organizations play an more and more important role in each society. The basis of environmental education in NGOs was created several decades before by activities of Slovak Union of Nature and Landscape Conservators (SZOPK) and Strom života. Besides them a lot of new initiatives raised up in the years after the political change, who work mostly on several projects on regional, but also national level. From the most successful projects Air pollution project Europe, The river watch, publications and visual aids for environmental education, summer camps, weekend activities in the field, building up a network of specialized NGO field centers for environmental education, trainings for teachers, activists and other are specifically named, or partly described. A special focus is given to international cooperation, especially in the field of trainings, which help to create an organizational background for NGO environmental education activities. International trainings are not only a matter of western know-how transfer to Slovakia, but also a matter of Slovak experience transfer to Eastern Europe already. One of basic principles for future successful development of environmental education in Slovakia is the cooperation of all involved sectors, especially of NGO sector with the government and with enterprises.