Electronic Journal of Differential Equations, Vol. 2005(2005), No. 50, pp. 1-10. Title: Existence of viable solutions for nonconvex differential inclusions Authors: Messaoud Bounkhel (King Saud Univ., Saudi Arabia) Tahar Haddad (Univ. of Jijel, Algeria) Abstract: We show the existence result of viable solutions to the differential inclusion $$\displaylines{ \dot x(t)\in G(x(t))+F(t,x(t)) \cr x(t)\in S \quad \hbox{on } [0,T], }$$ where $F: [0,T]\times H\to H$ $(T>0)$ is a continuous set-valued mapping, $G:H\to H$ is a Hausdorff upper semi-continuous set-valued mapping such that $G(x)\subset \partial g(x)$, where $g :H\to \mathbb{R}$ is a regular and locally Lipschitz function and $S$ is a ball, compact subset in a separable Hilbert space $H$. Submitted December 26, 2004. Published May 11, 2005. Math Subject Classifications: 34A60, 34G25, 49J52, 49J53. Key Words: Uniformly regular functions; normal cone; nonconvex differential inclusions.