The design of passive dampers involves the determination of the required capacity of each damper installed at selected locations. Generally, dampers with identical capacities are installed in various story units of a building. However, installing identical dampers in various story units does not achieve the optimal performance for the building and it may result in a conservative and more expensive design. In this paper, a design method, based on the concepts of active control theories, is proposed for the design of the capacities of passive dampers. For most of the passive dampers, the force applied to the structure depends on the drift and velocity across the dampers. From the standpoint of active control, the control force depends only on the local measurements of the displacement (i.e., drift across the damper) and velocity. Controllers of the form described above are designed by decentralized control theories. For this purpose, the method of static output optimal control is modified and applied to the design of passive dampers. Advantages of the proposed method for different types of passive dampers are demonstrated through numerical simulations.