Electronic Journal of Differential Equations, Vol. 2008(2008), No. 49, pp. 1-8. Title: Existence of least energy solutions to coupled elliptic systems with critical nonlinearities Authors: Gong-Ming Wei (Univ. of Shanghai for Science and Tech., China) Yan-Hua Wang (Shanghai Univ. of Finance and Economics, China) Abstract: In this paper we study the existence of nontrivial solutions of elliptic systems with critical nonlinearities and subcritical nonlinear coupling interactions, under Dirichlet or Neumann boundary conditions. These equations are motivated from solitary waves of nonlinear Schrodinger systems in physics. Using minimax theorem and by estimates on the least energy, we prove the existence of nonstandard least energy solutions, i.e. solutions with least energy and each component is nontrivial. Submitted October 18, 2007. Published April 04, 2008. Math Subject Classifications: 35B33, 35J50. Key Words: Least energy solutions; Nehari manifold; critical exponent; coupled elliptic systems.