Aspergillus sydowii is a globally distributed saprophytic soil fungus. It is commonly found in warm soils, but it has also been isolated from different plant substrates, including cotton, grains, straw and decomposing vegetation. However, it does not usually grow on foods as opposed to A. versicolor.

Known as an allergenic, Aspergillus sydowii has been associated with various health problems in humans that include aspergillosis of the lungs, disseminated aspergillosis otomycosis (ear infection), and onychomycosis (nail fungal infection). Although this type of mold had not been previously recognized as a marine pathogen, a recent event in the Florida coast where Gorgonian corals turned black and eventually died, showed that this mold is also an opportunistic pathogen that can affect sea life.