Recent findings on the role of the cell wall of pathogenetic fungi in the pathogenic processes of both vertebrates and invertebrates are presented. The fungal cell wall not only gives shape to the fungus, but it is a dynamic structure allowing fungal growth and survival of fungi in both friendly and adverse environments. It acts as a living sieve controlling the entry of nutrients and the secretion of metabolic products. In terms of fungal pathogenesis, the fungal wall may be responsible for eliciting the defense response of their respective invertebrate or vertebrate hosts or conversely it may provide protection against the host defense system during the pathogenic process.