One of the most important problems in software management of a very large and complex project such as Atlas is how to deploy the software on the running sites. By running sites we include computer sites ranging from computing centers in the usual sense down to individual laptops but also the computer elements of a computing grid organization. The deployment activity consists in constructing a well defined representation of the states of the working software (known as releases), and transporting them to the target sites, in such a way that the installation process can be entirely automated and can take care of discovering the context and adapting itself to it. A set of tools based on both CMT - the basic configuration management tool of ATLAS - and Pacman has been developed. The resulting mechanism now supports the systematic production of distribution kits for various binary conditions of every release, the partial or complete automatic installation of kits on any site and the running of test suites to validate the installed kits. This mechanism is meant to be fully compliant with the Grid requirements and has been tested in the context of LCG. Several issues related with the constraints on the target system, or with the incremental updates of the installation still need to be studied and will be discussed.