Waste-to-energy conversion such as anaerobic digestion has been widely promoted under the subsidies to decouple from fossil fuel dependence system and its inherent two-fold benefits. It could diversify the renewable energy matrix and divert the waste from the landfill. Co-digestion of two and more feedstocks could enhance bioenergy production and maximise waste recovery. However, the anticipated benefits are not absolute for all circumstances, varying across the type of co-substrate, pretreatment and other settings. The present study aims to overview the life cycle assessment (LCA) and the techno-economic assessment (TEA) of the anaerobic co-digestion processes. The results could provide an insight into the several critical parameters for sustainable co-digestion. Co-digestion of two or more feedstock is favourable since higher anaerobic digestion performances and higher profitability in TEA is shown. Cultivation of energy crops, transportation, pretreatment of feedstock and storage stage each contributes some shares to eutrophication potential (EP), acidification potential (AP), global warming potential (GWP), ozone depletion and fossil depletion. Generally, high anaerobic digestion performances and biogas upgrading can offset the negative environmental impact. Positive net present value is also observed from the co-digestion of feedstock.