Exploitation of natural capital generally leads to significant socioeconomic gains at the expense of biodiversity, despite identification of mitigation measures as part of Environmental and Social Impact Assessment (IA). This chapter considers the role of biodiversity offsets in achieving ‘no net loss’ of biodiversity, when implemented through IA as a logical final step in the sequence of mitigation measures generally referred to as the ‘mitigation hierarchy’. Offsets are a form of compensation that aims to achieve ‘no net loss’ or preferably a ‘net gain’ (NNL/NG) of biodiversity when development takes place. Because IA is used extensively for environmental planning and decision-making, the incorporation of a requirement to compensate or offset for these residual losses is seen as a potentially powerful way to reduce rates of biodiversity decline associated with development. Many countries now have policies or laws requiring offsets in some form and they are used by international financial institutions and a number of businesses to meet NNL/NG objectives. Reaction to biodiversity offsets as a way of achieving NNL/NG is mixed, however: some parties welcome them as an opportunity to ensure that residual negative impacts are compensated for; others fear that they represent ‘symbolic policy’, open to misuse by developers seeking to expedite development authorization, even when there is risk of irreversible losses of biodiversity that cannot be offset. This chapter explores biodiversity offsets in the context of impact assessment processes. It looks at offset practice around the world, considers how issues in offset design and implementation have been addressed and notes some emerging trends in offset practice that might help to address challenges and shortcomings.