The potential impacts and the environmental performance of the semi-aerobic landfill technology were assessed through the Life Cycle Assessment (LCA) methodology. Project data that referred to a hypothetical Italian plant design were used and ISO 14040/14044 standards were applied. All the life cycle phases were considered, from landfill construction to filling, aftercare, closure and conversion for future use. All the landfill processes and the inflow of materials, energy and rainwater, and the outflow of biogas and leachate, were included in the system boundaries. The results show that the overall environmental impacts associated to semi-aerobic landfill are primarily due to the filling and aftercare phases, but the impacts related to construction and closure phases are not negligible. The contribution analysis underlines the processes with major responsibility within the environmental profile, while the normalization of results demonstrates what are the environmental categories on which the landfill impacts fall most. Important lessons emerging from this research can support practitioners and scientists in optimizing semi-aerobic landfill design and management.