2005-Oujda International Conference on Nonlinear Analysis, Oujda, Morocco. Electronic Journal of Differential Equations, Conference 14 (2006), pp. 149-153. Title: Multiplicity results for nonlinear elliptic equations Authors: Samira Benmouloud (Univ. Ibn Tofail, Kenitra, Maroc) Mostafa Khiddi (Univ. Ibn Tofail, Kenitra, Maroc) Simohammed Sbai (Univ. Ibn Tofail, Kenitra, Maroc) Abstract: Let $\Omega$ be a bounded domain in $\mathbb{R}^{N}$, $N\geq 3$, and $p=\frac{2N}{N-2}$ the limiting Sobolev exponent. We show that for $f\in H^1_0(\Omega)^\ast$, satisfying suitable conditions, the nonlinear elliptic problem $$\displaylines{ -\Delta u =|u |^{ p-2 }u +f \quad \hbox{in } \Omega \cr u=0 \quad \hbox{on } \partial\Omega }$$ has at least three solutions in $H_{0}^{1}(\Omega)$. Published September 20, 2006. Math Subject Classifications: 35J20, 35J65. Key Words: Semilinear elliptic equations; critical Sobolev exponent.