It has been known that diabetes mellitus impairs functioning of neutrophil, macrophage, cellular immunity, humoral immunity, and iron metabolism. In addition to them, diabetes-related angiopathy leads a patient to being at high-risk individual for several kinds of infectious diseases. Therefore, diabetes has been accepted as one of the important risk factors for invasive fungal infection. From the viewpoint of pathology, the present review describes both pathophysiology of immunosuppression induced by diabetes and histopathological characteristics of typical forms in invasive fungal infection when it occurred as an opportunistic infection; those are candidiasis, aspergillosis, and cryptococcosis. We wish to draw that pathophysiological explanation still remains obscuring of relationship between diabetes and invasive fungal infection.