The introduction of non-indigenous species into an ecosystem has been known to create problems for existing species in that ecosystem. Further, in jurisdictions that share an ecosystem, the decision of one jurisdiction to permit the introduction of a species can affect the ecosystem shared with the other jurisdictions. The states of Maryland, Pennsylvania, and Virginia, and the District of Columbia, which share the Chesapeake Bay basin and are signatories to the 1987 Chesapeake Bay Agreement, seek to institute a process by which they can cooperate with one another in making decisions regarding the introduction of non-indigenous species. The Living Resources Subcommittee (LRSC) of the Chesapeake Bay Program was charged by the Implementation Committee with developing a policy to provide guidance to the Chesapeake Bay Agreement signatories on the intentional (e.g. rainbow trout) and unintentional (e.g. zebra mussel) introduction of non-indigenous aquatic species in the Chesapeake basin. This policy document considers only first time introductions of non-indigenous, non-naturalized aquatic species.