Distributing applications in distributed environment

Software distribution is a process of delivering software products to the users. It is an essential part of the software process. The complexity of this task increases in the highly geographically dispersed collaborations, such as modern HEP experiments. This paper focuses on general requirements to the software distribution system, main problems and various solutions. New requirements specific to the successful software operation in the GRID environment are discussed. We describe the current organization of the CMS software distribution and automated tools developed and used for the software distribution within the Collaboration.