During mycological investigation in beech and mixed forest stands growing in different climatic and ecological conditions carried out from 1990 to 2001, the author recorded fruiting bodies of fungi of the genus Nectria (F r.)F r. occurring on bark of beeches, fires and spruces. He found 10 Nectria species in 64 localities in 31 orographic complexes in Slovakia. Occurrence and distribution of species of the Nectria genus is characterised. Nectria coryli and N. punicea were rare. The taxonomical and nomenclatoric problems within the Nectria genus, as in the sexual stage (teleomorpha) as the asexual stage (anamorpha) is demonstrated by an example of selected authors. Out of this, some ecological characteristic of the Nectria genus are described.