The epidemiology of invasive fungal infections is evolving. Molds other than Aspergillus have emerged as significant pathogens in severely immunosuppressed patients. In most cases, the emergence of these infections seems to be a consequence of changes in the host accompanying more severe immunosuppression. The hyalohyphomycetes (molds that present in tissue as hyaline septate fungi) are a group of such emerging fungi. This article reviews the clinical spectrum, diagnosis, and management of infection caused by these pathogens, with a special emphasis on infection caused by Fusarium species.