This chapter examines comparative approaches to risk assessment and regulation of genetically modified organisms (GMOs). It first provides a brief background on the emergence, increased use, and controversy surrounding GMOs as well as the important legal questions and complexities they raise before discussing the legal approaches used to assess and regulate risks associated with GM foods, labelling of GM foods, and the application of intellectual property rights (IPRs) to GMOs. In particular, it considers risk assessment in the United States and in the European Union, focusing on the precautionary approach versus the permissive approach. It also compares process regulation and product regulation for regulating the risks posed by GMOs in the United States and the European Union, along with risk assessment and regulation in Brazil, China, and Costa Rica. Finally, it analyses the legal framework for IPRs as they apply to GMOs and comparative approaches to patenting GMOs.