Criminal procedure is the process related to the investigation, arrest, charging, and conviction or acquittal of a criminal defendant. Much of criminal procedure is comprised of processes and rules through which the government (state, federal, or municipal) enforces substantive criminal law and through which a criminal defendant’s Constitutional and other rights are protected.

The law of criminal procedure is primarily located in the applicable state or federal rules of criminal procedure and state and federal court opinions interpreting and applying Constitutional and other legal rights.

In New Mexico, criminal procedure is governed by a combination of state statutes, the New Mexico Rules of Criminal Procedure, and federal law, including Constitutional protections. These procedures outline the steps from the initial investigation of a crime to the arrest, charging, and eventual trial of a defendant. They ensure that a defendant's rights, such as the right to a fair trial, the right to counsel, and protection against self-incrimination, are upheld throughout the criminal justice process. The Fourth, Fifth, Sixth, and Fourteenth Amendments to the U.S. Constitution play a crucial role in criminal procedure, providing protections against unreasonable searches and seizures, the right to due process, and the right to a speedy and public trial by an impartial jury, among others. New Mexico's own constitution and court opinions also interpret and enforce these rights, ensuring that the state's criminal justice system operates within the legal framework established at both the state and federal levels.