Wireless communication systems are nowadays employed in many elds. The research effort beneath this work is to investigate one of the main issues in a radio communication system: interference. Devices operating in the 2.4 GHz ISM band are considered and, in particular, wireless sensors networks compliant to IEEE 802.15.4 standard are used to evaluate performance indices in the presence of interference. A complete perspective involving theoretical formulas, simulations and experimental results is given. The purpose of the work is to understand interference phenomena, using a real life test bed and a complex set of interferers comprising both arbitrary signal generators and real wireless networks. The interaction of interference with a device is manifold: it involves physical layer, hardware and protocols. The nal aim of this work is to provide protocol and hardware designers with a set of performance metrics and perspectives useful to improve wireless devices' behavior against interference.