A device for the administration by inhalation of a medicament in dry powder form comprises a medicament reservoir (9) and a medicament metering system (10) including a metering chamber (23) communicable with the reservoir (9), characterized in that the reservoir (9) is mounted in a housing (1) for rotation about an axis and the metering chamber (23) is located radially of the axis, the arrangement being such that the metering chamber (23) is charged with medicament during a charging rotation of the reservoir (9) about the axis.