Container closure integrity (CCI) is an increasingly relevant issue in the pharmaceutical packaging industry. It addresses the maintenance of integrity to prevent microbial ingress in sterile product packaging until the time of use, as well as to restrict the loss of product contents and to prevent the entry of detrimental gases or other materials. In order to ensure that CCI is guaranteed at all times, multiple aspects of parenteral packaging must be considered. This article by Geert Moens at Datwyler describes these considerations and highlights the steps being taken in the industry to ensure container closure integrity in a parenteral packaging system.