A criminal conspiracy is generally a partnership formed to commit a crime or crimes. A criminal conspiracy exists when two or more persons form an agreement to violate a law that includes criminal penalties, and then take one or more steps designed to accomplish the goal of the conspiracy.

Federal and state statutes make criminal conspiracies illegal for two primary purposes: (1) to help combat the powerful forces created when two or more people collaborate to commit a crime; and (2) to allow criminal prosecutors (state and federal) to prosecute persons who play a role in planning a crime but who are not involved in the physical acts taken to complete the underlying crime.

For example, under federal law, if two or more persons conspire either to commit any offense against the United States, or to defraud the United States, or any agency of the United States in any manner or for any purpose, and one or more of such persons do any act to accomplish the objective of the conspiracy, each of the conspirators may be fined under and imprisoned for up to five years. See 18 U.S.C. §371. And most states have statutes (usually located in the penal or criminal code) that make criminal conspiracies a crime and include significant punishment upon conviction.

In Oregon, criminal conspiracy is defined under ORS 161.450 as an agreement between two or more persons to commit a crime and an overt act in furtherance of the agreement. The state recognizes the seriousness of collaborative efforts to commit crimes and provides legal mechanisms to prosecute not only those who carry out the criminal acts but also those involved in the planning stages. The intent behind criminalizing conspiracy is to dismantle the collective power that individuals may have when working together to break the law and to hold accountable those who contribute to criminal endeavors, even if they do not execute the crime itself. Penalties for conspiracy in Oregon vary depending on the crime that the conspirators agreed to commit and can range from fines to imprisonment. This is in line with federal law, specifically 18 U.S.C. §371, which also criminalizes conspiracy to commit any offense against the United States or to defraud the United States, with potential fines and imprisonment of up to five years for those found guilty.