Electronic Journal of Differential Equations, Vol. 2011 (2011), No. 79, pp. 1-9. Title: Existence and asymptotic behaviour of positive solutions for semilinear elliptic systems in the Euclidean plane Authors: Abdeljabbar Ghanmi (Faculte des Sciences de Tunis, Tunisia) Faten Toumi (Faculte des Sciences de Tunis, Tunisia) Abstract: We study the semilinear elliptic system $$ \Delta u=\lambda p(x)f(v),\Delta v=\lambda q(x)g(u), $$ in an unbounded domain D in $ \mathbb{R}^2$ with compact boundary subject to some Dirichlet conditions. We give existence results according to the monotonicity of the nonnegative continuous functions f and g. The potentials p and q are nonnegative and required to satisfy some hypotheses related on a Kato class. Submitted March 31, 2011. Published June 20, 2011. Math Subject Classifications: 34B27, 35J45, 45M20. Key Words: Green function; semilinear elliptic systems; positive solution.