The influence of ecdysteroids on the complex process of ecdysis in both Crustacea and Insecta groups is analyzed. We will present a brief review of ontogeny of nerve cells in crustacean where ecdysis allows growth and maturation during the whole life cycle, and insects where the process allows metamorphosis from larval to adult stages. Main aspects of this review are oriented to show a comprehensive scope about the state of art of the action mechanisms of these hormones on nerve cells including from excitability to programmed cell death.