Abstract A cost-effective methodology is needed in various applications in order to optimise damping treatments for structures. Although some methods appear to be applicable for structures with relatively simple geometries, it is still difficult to utilise them for general structures. This paper presents an efficient approach for optimisation of passive damping treatments that can be applied to general structures. First, an optimisation procedure based on big bang–big crunch optimisation method is introduced and its effectiveness for damping optimisation is evaluated. Then, a procedure based on modal strain energy method is presented for the prediction of modal damping levels for structures with damping treatments and its performance is assessed. After that, for validation purposes, the proposed optimisation methodology is used to maximise modal damping for a single mode of a structure whose optimised configurations are known for the individual modes. Finally, the performance of the proposed optimisation procedure is demonstrated for the maximisation of damping levels for multiple modes at the same time and the applicability of the approach for general structures with passive damping treatments is demonstrated.