The stability properties of one-leg theta-methods for nonlinear neutral differential equations with proportional delay is investigated. In recent years, the stability of one-leg theta-methods for this class of equations on a quasi-geometric mesh is investigated. Instead, in the present paper, the focus is on stability of one-leg theta-methods for the neutral differential equations with constant delay obtained by applying the approach of transformation to the proportional delay equations. Some sufficient conditions for global stability and asymptotic stability are established. Two numerical examples are also included. (C) 2009 Elsevier Inc. All rights reserved.