Abstract: An apparatus for anesthetizing animals for slaughter has a gas chamber with an inlet at one end and an outlet at another end, and an inclined inlet ramp extending to the inlet of the chamber and a declined outlet chute for receiving anesthetized animals from the outlet of the chamber. The inlet ramp is sized to force the animals to proceed to the inlet in single file. A continuous belly conveyor extends through the gas chamber from the inlet, through an anesthetizing gas zone, and through the outlet for supporting the animals on their bellies and transporting them through the gas chamber in single file at a rate sufficiently slow to ensure each animal is rendered unconscious by the time it reaches the outlet. The conveyor has a pickup portion extending from the inlet of the chamber into the inlet ramp for receiving individual animals and supporting them on their bellies for introduction into the chamber.