This chapter considers the risk assessment of GM crops from a regulatory perspective. It is based on the experiences of the Organisation for Economic Co-operation and Development (OECD), which is an intergovernmental organisation.. Specifically, it describes how national authorities work together at OECD primarily to develop consensus documents which include information that regulators believe are important in risk assessment. Many of the documents address crops such as maize, soy bean, cotton, papaya, sugar cane and cassava, which have been the subject of genetic modification. Other documents address traits which have been introduced into crops through genetic modification such as herbicide tolerance and insect resistance. Although OECD is limited to thirty-five member countries, the OECD activities related to the risk assessment of GMOs are open to the active participation of a wider group of countries, including some developing countries and countries in transition, especially those with an interest and/ or experience in the risk assessment of GM crops. The consensus documents are intended as practical tools to assist in the risk assessment of transgenic crops.