The use of information and communication technology (ICT) is growing throughout society, and new products and solutions are developed at an increasing rate. To enable environmental assessment of specific ICT products and other products that rely on ICT in some way, a more complete, detailed, and up-to-date study based on real measurements is needed. To date, similar studies have not been readily available or fully comprehensive. This study assessed the overall operational electricity use and life-cycle?based carbon footprint (CF) relating to ICT in Sweden, including activities not commonly addressed previously, such as shared data transport networks and data centers and manufacturing of network infrastructure. Specific, detailed inventory data are presented and used for assessment of the Internet Protocol core network, data transmission, operator activities, and access network. These specific data, in combination with secondary, more generic data for end-user equipment, allow a comprehensive overall assessment. The majority of the ICT network CF is the result of end-user equipment, mainly personal computers, followed by third-party enterprise networks and data centers and then access networks. The parts closest to the user proved to be clearly responsible for the majority of the impact. The results are presented for Swedish ICT networks and for ICT networks in general based on a global average electricity mix.