This article studies the time-optimal output transition problem to change the system output, from an initial value y(t) = (y) under bar (for all time t <= 0) to a final value y(t) = (y) over bar (for all time t >= T), for invertible nonlinear systems. The main contribution of the article is to show that the use of pre- and post-actuation input outside the transition interval IIT = [0, T] can reduce the transition time T beyond the standard bang-bang-type inputs for optimal state transition. The advantage of using pre- and post-actuation is demonstrated with an illustrative nonlinear example. (C) 2011 Elsevier Ltd. All rights reserved.