The role of vacuum technology in the vacuum coating industry has changed significantly in the last 30 years. Previously the objective of producing a vacuum was to attain the best possible vacuum in the shortest time possible. In recent years to this goal has been added the requirements of establishing specific partial pressures of inert and reactive gases and vapors, generating uniform plasma environments and controlling the gas flow and gas distribution in the processing system. The vacuum systems are of ten required to handle toxic and corrosive gases and to tolerate fine particles generated in the processing. The increasing use of polymer substrates and rolls of films (webs) has increased the demands imposed for handling outgassing and desorption during vacuum processing. This paper will describe some of the problems and solutions used not only to address the problems of outgassing and desorption but also to minimize the problems by proper system design and substrate treatments in the vacuum system.