In the graduation thesis is presented evergreen oak, also known as holm oak (Quercus ilex L.), one of the main species from the mediterranean flora, that grows in Slovenia. The main goals of the thesis contained finding out the actual distribution of the species, morphological variability and finding out whether the species is endangered in the territory of Slovenia. On the field, we analyzed 7 different populations of the species, all of them in the Slovene littoral region. For the morphometric analysis, we gathered around 1100 leaves from 56 different trees. The variability of leaves between populations was observed. Between populations, a significat difference was confirmed for parameters: leaf area, leaf length, width to lenght ratio, leaf edge angle at 25% of the leaf's length and petiole length. Evergreen oak in Slovenia is a rare species, although it isn't affected by many factors that would additionaly endanger it. Because of climate change, the species will probably increase the size of the it's distribution range in the territory of Slovenia and will likely become more competitive compared to other tree species.