The Check Clearing for the 21st Century Act, commonly referred to as Check 21, is a federal law that enables banks to handle more checks electronically, which makes check processing faster and more efficient. It is designed to replace the old process whereby banks must physically move original paper checks from the bank where the checks are deposited to the bank that pays them, transportation that can be inefficient and costly. Check 21, which became effective on October 28, 2004, makes a “substitute check” (created using an image of the check) the legal equivalent of the original paper check. Under Check 21, banks can electronically transmit check images rather than physically moving the original paper checks between the receiving and paying banks. Check 21 applies to all types of checks: consumer, business, traveler’s and U.S. Treasury.  Check Clearing for the 21st Century Act ( Check 21) authorizes the use of a new negotiable instrument called a substitute check and facilitates the use of electronic check processing.  A substitute check is a paper reporoduction of an original check that contains and image of the front and back and is suitable for automated processing. This substitute check is a legal copy.