Diffuse x‐ray scattering from a single crystal of Cu3Au was observed atT/Tc≅0.995 where the long‐range order parameterSequals 0.85. By annealing at low temperatures, nearly perfect order was obtained. A difference curve yields the diffuse scattering attributable to short‐range order coexisting with the long‐range order state ofS=0.85. Analysis of the diffuse intensity in absolute units gives values of the first three short‐range order coefficients. The first coefficient is found to be close to the perfect order value: &agr;1=0.33. Within experimental error the observed coefficients fit both the Cowley theory and a random long‐range order model equally well.