This study reports on the whole genome sequencing of the hazelnut endophytic Fusarium isolate Hzn5 from Poland. It was identified as a member of the Fusarium citricola species complex based on a phylogenetic analysis which also pointed out that other hazelnut isolates, previously identified as F. lateritium and F. tricinctum, actually belong to this species complex. Genome annotation allowed the mapping of 4491 different protein sequences to the genome assembly. A further in silico search for their potential biosynthetic activity showed that predicted genes are involved in 1110 metabolic pathways. Moreover, the analysis of the genome sequence carried out in comparison to another isolate, previously identified as an agent of hazelnut gray necrosis in Italy, revealed a homology to several regions containing biosynthetic gene clusters for bioactive secondary metabolites. The resulting indications for the biosynthetic aptitude concerning some emerging mycotoxins, such as the enniatins and culmorin, should be taken into consideration with reference to the possible contamination of hazelnuts and derived produ