545 Copyright © 2016, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 21 DOI: 10.4018/978-1-4666-9644-0.ch021 ABSTRACT In the present chapter, we give an overview of iterative methods for linear complementarity problems (abbreviated as LCPs). We also introduce these iterative methods for the problems based on fxed-point principle. Next, we present some new properties of preconditioned iterative methods for solving the LCPs. Convergence results of the sequence generated by these methods and also the comparison analy- sis between classic Gauss-Seidel method and preconditioned Gauss-Seidel (PGS) method for LCPs are established under certain conditions. Finally, the efciency of these methods is demonstrated by numeri- cal experiments. These results show that the mentioned models are efective in actual implementation and competitive with each other. INTRODUCTION For a given real vector q R n ∈ and a given matrix A R nn ∈ × the linear complementarity problem ab- breviated as LCP (A, q), consists in finding vectors z R n ∈ such that w Az q z w zw T = + ≥ ≥ =      0 0 0 , (1.1) Verifcation of Iterative Methods for the Linear Complementarity Problem: Verifcation of Iterative Methods for LCPs H. Saberi Najafi Islamic Azad University, Lahijan Branch, Iran S. A. Edalatpanah Islamic Azad University, Lahijan Branch, Iran