The importance and status of European yew (Taxus baccata L.) in forest ecosystems in Slovakia are important knowledge for determining an appropriate strategy for conservation of this rare species. The dissertation thesis deals with the influence of selected ecological factors on growth processes, development, and morphology of the natural and artificial regeneration of yew. First of all, the thesis is oriented to the assessment of the natural and artificial regeneration of yew protected and unprotected against herbivory in forest stands with different light conditions. It deals with the analysis of the competition and diversity of tree species in forest communities with the occurrence of yew and the influence of selected tree species on the occurrence and growth of yew. The thesis is focused on the analysis of the herbivory damage of juveniles and the impact of herbivory pressure on the morphology of needle, morphology of root system and overall regeneration ability of yew. Study areas were oriented toward the most frequent occurrence of yew in Starohorské vrchy Mts. – Pavelcovo, Lackov grúň; in Veľká Fatra Mts. – Veľká Skalná and Strážovské vrchy Mts. There was also research object in Poland – Babki, where we studied the artificial regeneration of yew. The results of the thesis showed that herbivory damaged proved to be one of the most important factors influencing the establishment, development, and out-growing of yew juveniles. The intense herbivory pressure negatively affected the root morphology and needle morphology even after long-term exclusion of herbivores. The relationship between the height or number of yews and relative radiation was not significant, despite the wide measured spectrum of light intensity, because of high herbivory pressure in all study areas. Analysis of competition in study areas indicated that European beech is important competition tree species for yew, but there is also the high intra-species competition of mother trees to yew regeneration. In general, results confirmed problematic adolescence and out-growing of seedlings on all studied areas. Analysis of growth processes of natural regeneration in forest ecosystems in Slovakia underlined that yew deserves active management and protection against herbivory, otherwise its future would be unfeasible.