Paint and other coatings applied to the surfaces of many building materials provide important protective and decorative benefits. Paints protect the wood surface from weathering damage in most exterior uses of wood. Fungi and bacteria are the principal biotic destructive agents of paints under some use conditions or locations. Mildew is a common term in the paint and coating industry and used to deseribe an unsightly discoloration of a paint film and growth of mold fungi. This growth can occur on varieties of surfaces ineluding organic and inorganic origins, Approximately 100,000 species of mildew exist many of which affect the appearance and performance of fınishes. The aim of this article is to explain types of paint biodeterioration, the microflora of paint, the factors affecting mildew development, and general control practices,