The tax court has ruled that a tax return is not considered timely filed if it is lost by the U.S. Postal Service and it was not sent by registered or certified mail. In order to avoid the risk of your return being lost in the mail, and therefore, treated as not received by the IRS, you should mail the return via certified mail, return receipts requested. Save the receipt, and you will be presumed to have timely filed your return – even if it is not received by the IRS.
Sec. 7502. Timely mailing treated as timely filing and paying states the following:
(a) General rule
(1) Date of delivery
If any return, claim, statement, or other document required to be filed, or any payment required to be made, within a prescribed period or on or before a prescribed date under authority of any provision of the internal revenue laws is, after such period or such date, delivered by United States mail to the agency, officer, or office with which such return, claim, statement, or other document is required to be filed, or to which such payment is required to bemade, the date of the United States postmark stamped on the cover in which such return, claim, statement, or other document, or payment, is mailed shall be deemed to be the date of delivery or the date of payment, as the case may be.
(2) Mailing requirements
This subsection shall apply only if–
(A) the postmark date falls within the prescribed period or on or before the prescribed date–
(i) for the filing (including any extension granted for such filing) of the return, claim, statement, or other document, or
(ii) for making the payment (including any extension granted for making such payment), and
(B) the return, claim, statement, or other document, or payment was, within the time prescribed in subparagraph (A), deposited in the mail in the United States in an envelope or other appropriate wrapper, postage prepaid, properly addressed to the agency, officer, or office with which the return, claim, statement, or other document is required to be filed, or to which such payment is required to be made.
This section shall apply in the case of postmarks not made by the United States Postal Service only if and to the extent provided by regulations prescribed by the Secretary.
(c) Registered and certified mailing; electronic filing
(1) Registered mail
For purposes of this section, if any return, claim, statement, or other document, or payment, is sent by United States registered mail–
(A) such registration shall be prima facie evidence that the return, claim, statement, or other document was delivered to the agency, officer, or office to which addressed; and
(B) the date of registration shall be deemed the postmark date.
(2) Certified mail; electronic filing The Secretary is authorized to provide by regulations the extent to which the provisions of paragraph (1) with respect to prima facie evidence of delivery and the postmark date shall apply to certified mail and electronic filing.
This section shall not apply with respect to–
(1) the filing of a document in, or the making of a payment to, any court other than the Tax Court,
(2) currency or other medium of payment unless actually received and accounted for, or
(3) returns, claims, statements, or other documents, or payments, which are required under any provision of the internal revenue laws or the regulations thereunder to be delivered by any method other than by mailing.