<p><i>Ailanthus altissima</i> Mill. (Swingle), one of the worst invasive tree species in the world, represents an ecological burden on native forested ecosystems. In its management, numerous general removal procedures (including mechanical, chemical and biological) can be applied. Biological is one of the recent control strategies and the fungal strains are the most promising organisms in this field. Culturable fungal species from two wilting <i>A. altissima</i> stands in Slovakia were examined: a stand artificially treated with <i>Verticillium nonalfalfae</i> and a non-treated stand. The aim of this work was to a/ confirm the establishment of <i>V. nonalfalfae</i> in the treated stand, b/ investigate the fungi associated with symptomatic trees in the non-treated stand to determine if <i>V. nonalfalfae</i> spread may have occurred, and c/ consider the biological control potential of other isolated fungi identified. In stands, branches and leaves from wilting <i>A. altissima</i> were collected and cultured on agar. Resulting fungal colonies were sub-cultured for morphological and molecular identification. Eighteen fungal species were identified from 36 branch and 3 leaf samples from symptomatic trees within both stands. <i>Verticillium nonalfalfae</i> was isolated only from the treated stand while <i>V. dahliae</i> was isolated only from the non-treated stand. This confirms the establishment of <i>V. nonalfalfae</i> within the treated stand but does not confirm any additional spread. The isolation of <i>V. dahliae</i>, another known wilt-causing pathogen of <i>A. altissima</i>, from the non-treated stand indicates the natural presence of this pathogen. There have been no previous reports of Verticillium wilt caused by either species on <i>A. altissima</i> in Slovakia. A variety of other culturable fungal species were identified including a few species which were detected for the first time from <i>A. altissima</i> and five <i>Diaporthe</i> species, a genus that includes some known plant pathogens.</p>