This chapter discusses the environmental impact of insect rearing. Direct greenhouse gas (GHG) emissions from insects used as feed or food are discussed and data from life cycle assessments (LCAs) on commercially farmed insects are discussed per species. The relevance of the utilized feed on the environmental impact of insects and their derived products, including suggestions to lower this impact are also discussed. It is concluded that land use associated with insect production generally seems low, compared to conventional feed and food products. The EU (expressed as fossil fuel depletion) of insect production is often high compared to conventional products. To a large extent this is because several LCAs have been conducted for systems in temperate climates, which require extensive climate control.