Abstract:Black yeasts are a group of polymorphic yeast like fungi which produce melanin. They always grow slowly and have high stress resistance ability. The taxonomy, ecology, stress resistance, pathogenicity, and melanin of black yeasts are reviewed in this paper. Hortaea werneckii is an interesting novel model organism for studies on salt stress-responsive proteins as well as on sterol biosynthesis in eukaryotes. Aureobasidium pullulans is also like a model organism for studies on the regulation of polymorphic cell development.