Principles of risk assessment and management for release of biological control agents are explained. Example of the application of risk assessment and management is given based on the New Zealand practice and experience. Prior assessment and evaluation of potential adverse effects on environment and people of introducing any new organism into New Zealand is important in order to identify species that, if introduced could affect other biota, people, and the environment. This paper outlines the historical basis and current legislative regime for the management of potential effects of invertebrate new organisms proposed for release as biological control agent for arthropods. It describes the basis of the two main pieces of legislation the Hazardous Substances and New Organisms (HSNO) Act 1996 and the Biosecurity Act 1993 in the management of environmental effects of introduced organisms. The purpose of the HSNO Act is to protect the environment, and the health and safety of people and communities, by preventing or managing the adverse effects of hazardous substances and new organisms, while the Biosecurity Act is for the exclusion, eradication, and effective management of pests and unwanted organisms. The intentional release, in addition to importation, development, field testing, or conditional release, of all new organisms is managed under the HSNO Act. The HSNO Act is implemented by an independent agency the Environmental Risk Management Authority (ERMA New Zealand). The approach taken to prior determine the likely environmental effects of new organisms is outlined against the criteria in the HSNO Act as well as the risk assessment and management framework. A case study involving the release of an invertebrate biological control agent is mentioned as an example of the risk assessment framework used in New Zealand.