Neomycete is a mycological term denoting fungi (including FLOs or pseudofungi) introduced to an area or a country from other parts of the world, which means they are of foreign origin, i.e. allochthonous. As allochthonous species, unlike native or autochthonous species of fungi and pseudofungi, neomycetes are not found within their original distribution, but rather, they are introduced to new areas or habitats either accidentally or intentionally. Many of them are phytopathogenic species known as agents of various plant diseases, infecting cultivated and ornamental plants in particular. The objective of this thesis was to use the available literature (scientific and professional phytopathology papers, books, etc.) to define and describe phytopathogenic neomycetes infecting cultivated and ornamental plants in Croatia and to classify them based on their taxonomic ranks. A literature search has shown that 77 phytopathogenic neomycetes can be found in Croatia, 49 of which are species of fungi and 28 are species of pseudofungi. Every species of phytopathogenic neomycetes indicated is also accompanied by its valid Latin name, synonyms, origin, the most probable time of its appearance in Croatia, host plants they parasitise and their most important characteristics. The majority of phytopathogenic neomycete species come from the division Ascomycota, followed by Basidiomycota and Oomycota. Valid Latin names of phytopathogenic fungi and pseudofungi and their synonyms provided in this thesis correspond to the Index Fungorum online mycological database.