In this paper a minimum distance detector is implemented for the first time, to decode equiprobable ultra-wide band (UWB) chipless radio frequency identification (RFID) tags in an additive white Gaussian noise (AWGN) channel. The coding of the UWB chipless tags is performed by changing the position of the resonance dip in order to increase the Euclidean distance (ED) between different codes. Four UWB chipless RFID tags are successfully decoded verifying the viability of this decoding technique and their coding performance is evaluated calculating their detection error probability.