Mycobiota inhabiting symptomatic leaves of Fraxinus excelsior from two sites in Asturias, northern Spain, was analyzed to investigate the occurrence of pathogenic fungal species on European ash such as Hymenoscyphus fraxineus Leaves were collected in fall 2014 and isolations were made from petioles showing discolorations. The morphological characterization of 173 isolates resulted in eight morphotypes, whereas the phylogenetic analysis resulted in seven genera, AlternariaPhomopsis and Phoma being the most frequently isolated. Neither H. fraxineus, nor other Hymenoscyphus species were detected. The absence of H. fraxineus is consistant with field observations where no typical ash dieback symptoms were recorded. Most of the fungi isolated are known plant pathogens and some of them have occasionally produced disease symptoms on ash after artificial inoculations. Nevertheless, their natural behaviour as pathogens on F. excelsior remains unclear, and could be significantly influenced by different factors as environmental conditions or endophyte presence.