This Recommendation aims to provide a methodology for evaluating the environmental impact of ICTs objectively and transparently, and is based upon the life cycle assessment (LCA) methodology standardized in [ISO 14040] and [ISO 14044]. This Recommendation can be read by anyone aiming for a better understanding of the specific conditions and requirements applicable to the LCA of ICT goods, networks and services (GNS). However, the Recommendation is especially intended for LCA practitioners with a prior knowledge of LCA standards, i.e., [ISO 14040] and [ISO14044].