The era of Internet-of-Things is leading to the widespread of sensors in medical and consumer applications, where electronics is aiming at being wireless, battery-less, lowcost and wearable. In this context, pressure sensors are of particular interest since they can be used to monitor parameters such as human posture, motion and interaction with the environment. This paper presents a novel zero-power pressure sensor with wireless communication and wireless powering feature, with a flexible sensing element. The key component of the sensor is a Schottky-diode harmonic transponder connected to a piezoresistive transducer. The piezoresistor is placed along the DC path of the rectifier circuit in order to control the rectifying behaviour of the diode and thereby encoding the information about pressure on the backscattered signal. This sensor is a proof of concept of a novel fully-passive and wireless pressure sensor with a flexible sensing element.