Aspergillus ostianus is a species of fungus in the genus Aspergillus. It is from the Circumdati section. The species was first described in 1899. It has been reported to produce ochratoxin A.
A. ostianus has been cultivated on both Czapek yeast extract agar (CYA) plates and Malt Extract Agar Oxoidî (MEAOX) plates. The growth morphology of the colonies can be seen in the pictures below.