Electronic Journal of Differential Equations, Conference 09 (2002), pp. 117-126. Title: Existence of stable periodic solutions for quasilinear parabolic problems in the presence of well-ordered lower and upper-solutions. Authors: Abderrahmane El Hachimi (Faculte des Sciences El Jadida, Maroc) Abdelilah Lamrani Alaoui (Faculte des Sciences El Jadida, Maroc) Abstract: We present existence and stability results for periodic solutions of quasilinear parabolic equation related to Leray-Lions's type operators. To prove existence and localization, we use the penalty method; while for stability we use an approximation scheme. Published December 28, 2002. Math Subject Classifications: 35K55, 35B20, 35B40. Key Words: Leray-lions operator; penalization; lower and upper-solutions; monotone process; periodic solutions; stabilization.