To impart disturbance rejection properties is an important goal in the design of an appropriate process control structure. In a multivariable control system, the effectiveness of disturbance rejection can depend strongly on the direction of the disturbance. In this paper, we present a study of the controllability and disturbances effect for a general nonlinear plant. For this purpose, controller-independent measures are defined and computed by solving a simple optimization problem in the time-domain. Finally, several examples are considered to illustrate the proposed method. (C) 2004 Elsevier Ltd. All rights reserved.