Seasonal variations in the mycoflora of outdoors air and sedimented dust were studied at Assiut (extreme-arid region) over a period of two years during January-December 1985 and 1986 (monthly two samples) using, respectively, the settle plate-method and the dilution plate-method. 108 species and 3 species varieties belonging to 37 genera were collected from the air (32 genera and 89 species + 2 varieties) and sedimented dust (33 genera and 92 species + 3 varieties) on glucose-Czapek Dox agar at 28°C. The total counts of fungi in air and sedimented dust showed seasonal fluctuations giving maxima, respectively, during April and December 1985; and February and November 1986. There were basic similarities between the mycoflora of air and sedimented dust with the most frequently genera being:Alternaria(5 species in air and dust),Aspergillus(20+2 varieties),Cochliobolus(7),Penicillium(16),Pleospora(1) andUlocladium(7). Their counts irregularly fluctuated giving peaks at various months. Of the above genera,Alternaria alternata, A. chlamydospora, A. tenuissima, Aspergillus flavus, A. flavusvar.columnaris, A. fumigatus, A. japonicus, A. niger, A. ochraceus, A. sydowii, A. terreus, Cochliobolus hawaiiensis, C. lunatus, C. spicifer, Penicillium aurantiogriseum, P. chrysogenum, P. citrinum, P. oxalicum, Pleospora herbarum, Ulocladium atrumandU. botrytiswere the most prevalent species. The best counts of these species were recorded at various months. Several fungi were more common in the atmosphere compared with sedimented dust and vice versa.