Electronic Journal of Differential Equations, Vol. 2013 (2013), No. 95, pp. 1-14. Title: Asymptotic behavior of positive solutions of a semilinear Dirichlet problem outside the unit ball Authors: Habib Maagli (King Abdulaziz Univ., Rabigh, Saudi Arabia) Sameh Turki (Faculte des Sciences de Tunis, Tunisia) Zagharide Zine El Abidine (Faculte des Sciences de Tunis, Tunisia) Abstract: In this article, we are concerned with the existence, uniqueness and asymptotic behavior of a positive classical solution to the semilinear boundary-value problem $$\displaylines{ -\Delta u=a(x)u^{\sigma }\quad\text{in }D, \cr \lim _{|x|\to 1}u(x)= \lim_{|x|\to \infty}u(x) =0. }$$ Here D is the complement of the closed unit ball of $\mathbb{R} ^n$ ($n\geq 3$), $\sigma<1$ and the function a is a nonnegative function in $C_{\rm loc}^{\gamma}(D)$, $0<\gamma<1$, satisfying some appropriate assumptions related to Karamata regular variation theory. Submitted February 7, 2013. Published April 11, 2013. Math Subject Classifications: 31C35, 34B16, 60J50. Key Words: Asymptotic behavior; Dirichlet problem; subsolution; supersolution.