Abstract: The present disclosure relates to a device (10) and method for measuring the resistance of inhalers (20) to air flow. In particular, the device and method can be used to measure the resistance to air flow of dry powder inhalers (20), which are used for pulmonary drug delivery. The device (10) has a pair of chambers (12, 18) to mount and enclose an inhaler (20) within. Each chamber (12, 18) has a respective valve. The device (10) has further a pressure controller (22), a flow controller (24) and pressure and flow sensors and microprocessors configured to control opening and closing of the valves and to detect and analyze the corresponding signals.