A transfer system (100, 100′, 100″) adapted to allow first contents of a first container (20) and second contents of a second container (30) to mix to form a material. The mixed material is retrieved to a syringe (40). The transfer system (100, 100′, 100″) comprises first (17) and second (18) flow control members for controlling fluid flow between the containers (20, 30) and the syringe (40). The invention further relates to a drug mixing kit comprising a container unit containing first and second containers, and a transfer unit comprising ports for receiving the containers and a syringe and a number of flow channels. The container unit and the transfer unit are adapted to be coupled together to form a drug mixing kit.
