An aseptic sampling system comprises sampler and interface assemblies. Each assembly comprises a housing defining separate sterile enclosures. An air lock provides aseptic joining of the enclosures within the sampler and interface assemblies, and a re-sealable liquid connection mechanism operates within the lock. The sampler and interface assemblies, when connected, form an outer protective surface comprising the housings of the sampler and interface assemblies, the protective surface providing a sterile internal enclosure and air lock and an air-tight barrier between outer non-sterile, and inner sterile, atmospheres. The connection mechanism, contained within the sterile enclosure, contains at least one liquid connector from each of the sampler and interface assemblies, configured such that at least one of the connectors moves across the enclosure and lock to connect with the other connector in the connection mechanism, without contacting internal surfaces within the lock, and the connectors can be re-sealed, disconnected and separated.