<P> A Taxpayer Identification Number (TIN) is an identifying number used for tax purposes in the United States . It is also known as a Tax Identification Number or Federal Taxpayer Identification Number . A TIN may be assigned by the Social Security Administration or by the Internal Revenue Service (IRS). </P> <P> Section 6109 (a) of the Internal Revenue Code provides (in part) that "When required by regulations prescribed by the Secretary (of the Treasury or his delegate) (...) Any person required under the authority of this title (i.e., under the Internal Revenue Code) to make a return, statement, or other document shall include in such return, statement or other document such identifying number as may be prescribed for securing proper identification of such person ." </P>

Where do i get my tax identification number