Summary: We present a technique of approximating design sensitivities of the critical load. The technique results in stable estimations of design sensitivities at prebuckling points. Since taking derivatives of an approximated eigenvalue problem gives unstable sensitivities as the prebuckling point approaches the critical load, the sensitivities are approximated directly from exact sensitivity expressions. The sensitivities are approximated by applying two common approaches that are used in the critical load estimation, and are called ‘one- and two-point approximation’. The reliability and applicability of the proposed technique are demonstrated through numerical examples of truss and beam structures. It turns out that the two-point approximation of design sensitivities gives better results than the one-point approximation.