ESDU Struct 01.01.23 provides graphs from which the flexural buckling load on a composite strut of two components may be determined for all combinations of simply-supported and clamped end conditions and of clamped and free end conditions (excluding free-free). The graphs, each of which applies to one pair of end conditions, give a series of curves for the buckling load. Each curve is for a value of the ratio of the product of the modulus of elasticity of the material of a chosen first component and the minimum moment of inertia of its section to that product for the second component; the curves are plotted against the ratio of the length of the second component to the overall length of the composite strut. The buckling load is plotted in a non-dimensional form, factored by the square of the total length of the strut and divided by the product of the modulus of elasticity of the material of the second component and the minimum moment of inertia of its section. It is assumed that each component of the strut is of constant flexural rigidity. It is also assumed that the two components are rigidly attached end to end, that their centroids lie on the axis of loading, and that their axes of minimum inertia are co-planar. The curves may also be applied to a symmetrical strut of three components. The basis of the curves is theoretical, and the equations from which they were derived are given. A worked example illustrates the use of the data.