A delivery device is provided which comprises a container containing a dose of a powder and having at least one exit orifice for dispensing the dose from the container and a chamber adapted to receive the container in an operative configuration. The device further comprises at least one gas inlet by which gas may enter the chamber and at least one gas outlet by which gas and entrained powder may exit the chamber. The delivery device is operable to generate a gas flow through the chamber between the at least one gas inlet and the at least one gas outlet, which brings about orbital motion of the container within the chamber in that at least a central region of the container orbits a central axis of the chamber. The volume occupied by the container is at least 25% of the volume of the chamber.