Mutual legal assistance treaty

A mutual legal assistance treaty (MLAT) is an agreement between two or more countries for the purpose of gathering and exchanging information in an effort to enforce public or criminal laws.

Modern states have developed mechanisms for requesting and obtaining evidence for criminal investigations and prosecutions.

When evidence or other forms of legal assistance, such as witness statements or the service of documents, are needed from a foreign sovereign, states may attempt to cooperate informally through their respective police agencies or, alternatively, resort to what is typically referred to as requests for “mutual legal assistance.

"[1] The practice of mutual legal assistance developed from the comity-based system of letters rogatory, though it is now far more common for states to make mutual legal assistance requests directly to the designated Central Authority within each state.

[1] For instance, the Convention on Mutual Administrative Assistance in Tax Matters is a convention to facilitate the entering into bilateral tax information exchange agreements between more than 90 states parties.