Disassembly is a process which is applied for reusing abandoned goods and materials, the aim is to protect the environment and to regain the value added to products. In addition, by applying disassembly, future high disposal costs imposed by legislation can be avoided. The hazard of the entire disassembly process is enormous because of lack of information concerning the discarded goods. In order to make the disassembly process economically viable at the current state of the art, a comprehensive disassembly strategy is required. Its main task is to determine the disassembly level and disassembly sequences which provide conditions of the generation of profit while the environmental conditions are maintained. A review of the available theories is presented which are proper for the creation of a disassembly strategy. These theories together with a new mathematical tool result into a comprehensive methodology for the determination of a disassembly strategy. This methodology is illustrated by solving a practical disassembly problem which shows the benefits of its applicability.