To contribute towards the knowledge of microbiology of feeds, more than 100 samples of poultry feed mixtures from Slovakia were mycologically investigated in terms of the overall fungal diversity and toxicological potential of isolated fungi. The study revealed that out of 22 genera recovered, Penicillium was the most frequent and diverse genus, followed by Aspergillus and Mucor being found in 89% (34 spp.), 69% (11 spp.) and 50% (4 spp.), respectively. The most frequently encountered taxa were Fusarium proliferatum, followed by Penicillium aurantiogriseum, Mucor racemosus, Penicillium crustosum and Aspergillus flavus. In addition, the following genera were recorded (in descending order) Rhizopus (44%, 3 spp.), Eurotium (42%, 5 spp.), Fusarium (42%, 3 spp.), Cladosporium (31%, 1 sp.), Alternaria (22%, 3 spp.), Absidia (16%, 3 spp.), Acremonium (12%, 2 spp.), Scopulariopsis (10%, 2 spp.), Paecilomyces (4%, 1 sp.), Ulocladium (3%, 1 sp.), Trichoderma (2%, 1 sp.), Zygorrhynchus (2%, 1 sp.), and finally Emericella, Epicoccum, Geosmithia, Monascus, Stachybotrys, Syncephalastrum and Wardomyces, all were encountered in 1% of the samples being represented by a single species. The mean value counts of total fungi ranged from 1 × 103 to 200 × 105 cfu/g. Outcomes from mycotoxin screening within the appropriate potentially toxinogenic species showed a number of mycotoxin producers, namely those forming aflatoxin B 1 (n=3), citrinin (17), cyclopiazonic acid (76), fumonisin B 1 (86), griseofulvin (42), moniliformin (18), ochratoxin A (5), patulin (56), penitrem A (30) and sterigmatocystin (10).