Electronic Journal of Differential Equations, Vol. 2006(2006), No. 69, pp. 1-10. Title: Existence of weak solutions for nonlinear elliptic systems on $\mathbb{R}^N$ Authors: Eada A. El-Zahrani (Faculty of Science for Girls, Saudi Arabia) Hassan M. Serag (Al-Azhar Univ., Cairo, Egypt) Abstract: In this paper, we consider the nonlinear elliptic system $$\displaylines{ -\Delta_pu=a(x)|u|^{p-2}u-b(x)|u|^\alpha|v|^\beta v+f,\cr -\Delta_qv=-c(x)|u|^\alpha |v|^\beta u + d(x) |v|^{q-2}v +g ,\cr \lim_{|x|\to\infty}u=\lim_{|x|\to\infty}v=0\quad u,v>0 }$$ on a bounded and unbounded domains of \mathbb{R}^N, where $\Delta_p$ denotes the p-Laplacian. The existence of weak solutions for these systems is proved using the theory of monotone operators Submitted February 9, 2006. Published July 6, 2006. Math Subject Classifications: 35B45, 35J55. Key Words: Weak solutions; nonlinear elliptic systems; p-Laplacian; monotone operators.