Mail theft includes stealing or taking any posted item, including packages and postcards. This crime does not require the use of force; the taking of things through fraud, deception, or embezzlement is included within the definition of the crime. The mail thief need not intend to keep the mail they are taking. Hiding or destroying mail is also mail theft, as is the purchase, receipt, or possession of stolen mail.

Sometimes mail is left unattended by postal workers, which can open the door to theft. Mail theft occurs when mail is wrongfully taken from either the post office or a mailbox, as well as when a mail item is taken from a place left for collection on or adjacent to a collection box or authorized depository.

A conviction for mail theft under 18 U.S. Code § Section 1708 carries potential penalties of fines and federal prison sentences of up to five years.