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 New York, criminal conspiracy is defined under Article 105 of the New York Penal Law. A criminal conspiracy occurs when two or more persons agree to engage in or cause the performance of conduct that constitutes a crime, and at least one of them commits an overt act in furtherance of the conspiracy. The severity of the charge in New York depends on the underlying crime that the conspirators intended to commit, ranging from a misdemeanor for conspiring to commit a misdemeanor, to a class A-I felony for conspiring to commit a class A-I felony. The purpose of these laws is to deter the collaboration in criminal activities and to allow for the prosecution of those involved in the planning stages of a crime, even if the crime itself is not completed. Under federal law, as per 18 U.S.C. § 371, a conspiracy to commit any offense against the United States or to defraud the United States or any agency thereof involves potential fines and imprisonment for up to five years. Both New York State and federal laws aim to disrupt and penalize the collaborative efforts to commit crimes before they can be brought to fruition.