This review involves generalized data on extracellular proteases of filamentous fungi. General characteristics of secreted proteases and their classification are considered. Analysis of the data available revealed that fungi secrete only serine, aspartyl, and metalloproteases. Nothing is known about secretion of cysteine proteases; some available data do not have clear experimental evidence. Physicochemical and kinetic properties of the most typical extracellular proteases of different classes and families are discussed in detail. Special attention is focused in the review on regulation of synthesis of extracellular proteases and participation of the secreted proteases of pathogenic fungi in the infection process in animals, insects, or plants.