This paper presents an AMR (Automated Meter Reading) system based on IEEE 802.15.4. It uses low-power routers and end-devices, which are in the SLEEP mode most of the time, so that the wireless network can operate for more than 10 years using low-cost batteries. This paper presents the main features of the proposed network protocol, and a hardware implementation in the 868 MHz ISM band. A pilot has been also deployed in the Cartuja Island in Seville to assess system performances.