Animal research guidelines emphasize the need for researchers to be able to euthanize animals when required. Some field biologists rarely encounter the need to euthanatize animals, so may not develop competence or feel confident in the use of physical means. At the same time, there are increasing restrictions on the types of drugs that can be used in the field, and veterinary assistance may be far away should it be needed. For these situations, there is a pressing need for a transportable and reliable method of euthanizing animals. The use of CO₂ has been recommended for euthanasia for a variety of taxa so a small and lightweight euthanasia device was developed using a mini-regulator and a pre-set outlet tap to deliver CO₂ at rates suitable to comply with veterinary guidelines. The device and the necessary CO₂ cartridges can easily be stored and transported in a small container that can also act as the receiving chamber.