The research concerning endangerment of Yellow azalea (Rhododendron luteum Sweet) in its natural habitats in Slovenia was carried out in Dolenjska region. In Slovenia this species is classified as protected and endangered one so special precautionary measures in order to assure its long-term preservation need to be taken. The main goals of our research were: inventory and evidence of all natural resources of this species in Slovenia, inventory of all specimen on the surface, establishment of health condition, evaluation of regeneration on individual surface, study of morphological leaf variability and proposing long-term measures to preserve all Slovenian populations. The research was carried out at three well-known resources in Boštanj, Vrhek and Gabrje as well as at four new recorded resources in Krmelj, Mokronog, Vrh nad Boštanjem in Apnenik. The findings show that in general health condition of specimen at individual resources is stable, whereas in some parts they are endangered by visitors who dig up or break stems. In the future more attention should be given by institutions or individuals who are responsible for them. The most stable and vital is the population in Boštanj. On the other hand a large number of less vital specimen is noticed in Gabrje. All populations are good at regeneration. 216 stems and 1606 leaves were included in the morphometric leaf analysis. Elements that show maximum variability are: leaf blade width, stalk length and angle at 90 % of leaf surface length.