Sterile pharmaceutical products such as live viral vaccines, gene therapies, and products that contain active cells often require deep cold storage, either at -80°C or cryogenic temperatures (-196°C) to maintain stability and/or activity. These storage conditions pose a challenge to the packaging components. It is therefore essential to generate robust data that demonstrates the maintenance of seal integrity during deep cold storage and/or transport which, in turn, requires a robust container closure integrity (CCI) test method. This article describes the development of such a test method for vials stored at -80°C.