Metal Theft Prevention Act of 2013 - Prohibits stealing specified metal being used in or affecting interstate or foreign commerce, the theft of which harms critical infrastructure, including metal used as part of an electrical substation, power line, cellular tower, telephone land line, highway equipment and facilities, railroad equipment and facilities, water well, reservoir, or sewage line. Sets penalties of a fine, 10 years' imprisonment, or both, for violations.

Defines "specified metal" to include metal that is: (1) marked with the name, logo, or initials of a city, county, state, or federal government entity, a railroad, an electric, gas, or water company, a telephone company, a cable company, a retail establishment, or a public utility; (2) part of certain infrastructure items, such as a street light pole, guard rail, storm water grate, or grave marker; (3) a wire or cable commonly used by communications and electrical utilities; or (4) copper, aluminum, and other metal that is valuable for recycling or reuse as raw metal (except for aluminum cans).

Prohibits a recycling agent from purchasing such metal: (1) unless the seller provides documentation of ownership of, or other proof of the authority of the seller to sell, such metal and there is a reasonable basis to believe that the documentation provided is valid (does not require the agent to independently verify such validity); or (2) that the agent knows, or has a reasonable basis to believe, to be stolen. Subjects violators to a civil penalty of up to $10,000 per violation.

Sets forth recycling agent record-keeping and confidentiality requirements. Prohibits a recycling agent from paying cash for a single purchase of such metal of more than $100. Considers more than 1 purchase in any 48-hour period from the same seller to be a single purchase.

Exempts from such documentation requirements or purchase limits any recycling agent that is subject to a state or local law that requires obtaining such documentation or that limits such purchases.

Authorizes specified enforcement actions by the Attorney General and state attorneys general or equivalent state regulators.

Directs the U.S. Sentencing Commission to review and amend the Federal Sentencing Guidelines and policy statements applicable to a person convicted of the theft of such metal.