A　layerwise　(zigzag)　finite　element　formulation　is　developed　for　the　buckling　analysis　of　stiffened　laminated　plates.　The　laminated　plate　is　discretized　into　layers　along　the　thickness　direction.　Each　layer　of　the　laminated　plate　is　modeled　by　the　degenerated　shell　elements,　and　the　stiffener　is　modeled　by　the　general　3-D　beam　elements.　Layers　are　stacked　together　according　to　the　interlayer　continuity.　In-plane　displacements　are　considered　in　the　derivation　of　geometric　stiffness　matrix.　The　advantage　of　the　proposed　model　is　its　applicability　to　both　thin　and　thick　laminated　plates.　The　significance　of　this　study　lies　in　the　disclosure　of　the　interaction　between　the　lateral　buckling　of　the　stiffener　and　the　buckling　of　the　laminate.　The　inverse　iteration　method　is　adopted　to　extract　the　lowest　eigenvalue　corresponding　to　buckling.　Parametric　and　comparative　studies　are　conducted　for　different　plate　aspect　ratios,　plate　thickness　to　length　ratios,　degrees　of　layer　orthotropy,　ply　orientations,　and　stiffener　depth　to　plate　thickness　ratios.　(C)　2002　Elsevier　Science　Ltd.　All　rights　reserved.