Omphalitis associated with aspergillosis was diagnosed in four cases of commercial turkey poults ranging in age from 3 to 9 days old. In two cases, the mycotic agent present in the yolk sac was isolated and identified as Aspergillus fumigatus. In the other two cases, the fungi were identified as Aspergillus sp. on the basis of morphologic characteristics of the fungi in tissue sections. The fungi present were further confirmed to be of the genus Aspergillus by immunohistochemistry. Omphalitis by A. fumigatus infection has not been documented before.