Functionally graded materials (FGMs) have received considerable attention in many engineering applications since they were ?rst reported in 1984 in Japan (see Koizumi, 1993). FGMs are composite materials, microscopically inhomogeneous, in which the mechanical properties vary smoothly and continuously from one surface to the other in one (or more) direction(s). This is achieved by gradually varying the volume fraction of the constituent materials. FGMs were initially designed as thermal barrier materials for aerospace structural applications and fusion reactors. FGMs are now developed for general use as structural components in extremely high temperature environments. Unlike ?ber–matrix composites which have a mismatch of mechanical properties across an interface of two discrete materials bonded together and may result in debonding at high temperatures, FGMs have the advantage of being able to withstand high temperature environments while maintaining their structural integrity. Thus, FGMs are finding applications in many fields such as aerospace, power generation industries, and energy conversion. With the increased usage of these materials, it is important to understand the buckling and post buckling behaviors of functionally graded circular plates. Circular plates made of functionally graded materials are often employed as a part of engineering structures. Studies on FG circular plates are, however, rare in comparison with those available on FG rectangular plates. Most widely known type of FGM is a combination of metal and a refractory ceramic. An axisymmetric and asymmetric post buckling analysis is presented for a functionally graded circular plate subjected to in-plane and transverse mechanical loading. Material properties are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The governing equations of a functionally graded circular plate are based on the first-order shear deformation plate theory with von Karman non-linearity. Introducing a stress function and a potential function, the governing equations are uncoupled to form equations describing the interior and edge-zone problems of FG plates. This uncoupling is then used to conveniently present an analytical solution for the non-linear axisymmetric and asymmetric post buckling of an FG circular plate. A perturbation technique, in conjunction with Fourier series method to model the problem asymmetries, is used to obtain the solution for clamped and simply supported boundary conditions. The results are verified in four cases by comparison with the existing results in the literature. For the purpose of numerical illustrations, two material systems of FGM, aluminum–zirconia and aluminum–alumina will be considered. The effects of material properties, boundary conditions, and boundary-layer phenomena on various response quantities in a solid circular plate are studied and discussed. It is observed that the boundary-layer width is approximately equal to the plate thickness with the boundary-layer effect in simply supported FG plates being stronger than that in clamped plates. It is found that unlike simply supported FG plates the bifurcation phenomenon exists in clamped plates. Results also show that the amounts of the radial stress resultant in FG plates lie between those of a fully metallic plate and a ceramic plate for all edge supports. Keywords: Functionally graded material, Post buckling, Perturbation, Bifurcation ,Potential function