Both wrinkling and "quasi-Euler" buckling modes of sandwich plates have hitherto been taken as sinusoidal. In this report the possibility of nonsinusoidal modes is investigated. The core slab material considered is the special orthotropic one which does not resist deformation in its own plane, but only extension and shear­ ing perpendicular to its plane. This choice is made for two reasons: (1) such an idealized core material has been adopted by previous investigators as closer to certain real cores than the iso­ tropic material, and also because the "in the plane" stress com­ ponents are believed to play but a minor part in the core action, (2) it permits a relatively simple analysis of nonsinusoidal defor­ mations and the satisfaction of end conditions which would pre­ sent formidable analytical difficulties if the core were isotropic. It is found that the critical wrinkling loads corresponding to sinusoidal modes are not the lowest consistent with "pinned" ends. Loads about half as great correspond to buckling modes in which the deformation is confined to the end zones. The main body of the panel remains flat but undergoes a lateral displace­ ment. The effect of clamping the ends is also examined. The pattern of the theory follows closely, though not exactly, that of the long column with elastic foundation considering end conditions other than simple support. Ratzersdorfer4 showed that when the ends are allowed to deflect the critical load is halved, and the deflection localized at the ends. The problem is the same when the ends are pinned but the rigid base of the elastic foundation is freed to "float" under no forces other than those of the springs representing the foundation. This is a close analog of the sandwich problem.