Spores of Neurospora crassa 74A are lacking in ferritin like iron pools, as demonstrated by Mossbauer spectroscopic analysis. The cyclic hexapeptide siderophore ferricrocin constituted 47% of the total iron content in spores. After germination and growth, the ferricrocin iron pool disappeared, indicating that the metal was utilized. In spores of Asperigillus ochraceus, 74% of the total iron content was bound by ferrichrome-type siderophores. Siderophores may function as iron storage forms in fungal systems.