In this article, a very brief description of the importance of physical protection systems for nuclear facilities will be discussed. Asystematic and measurable approach to the implementation of a PPS will be described in a comprehensive manner. For this purpose, the design objectives of PPS will be discussed. Various deterrence measures will be described with the caution or not to depend on deterrence measures for protection of assets and must be supplemented by detection. It will also briefly introduce the main PPS functions, detection, delay and response along with the relationship of these functions. It will emphasize the function of detection, followed by delay and response. Specific performance measures of various functions of a PPS will be described, along with how these measures are combined to support a cost–benefit analysis. The process stresses the use of integrated systems combining people, procedures, and equipment to meet protection objectives.