SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 UNITED STATES FORM 10-D ASSET-BACKED ISSUER THE SECURITIES EXCHANGE ACT OF 1934 For the monthly distribution period from (Exact name of depositor as specified in its charter) (State or other jurisdiction of incorporation or organization of the issuing entity) (Telephone number, including area code) 010 1 -~~May~~ J u n -07 0 7 Structured Asset Securities Corporation (I.R.S. Employer Identification No.) 74-2440850 (Address of principal executive offices of issuing entity) (Zip Code) DISTRIBUTION REPORT PURSUANT TO SECTION 13 OR 15(d) OF to 02-~~Apr~~May-07 (Exact name of issuing entity as specified in its charter) Commission File Number of Issuing entity: 333-133985-59 Commission File Number of depositor: 333-133985 (Exact name of sponsor as specified in its charter) Lehman Brothers Holdings Inc. (Former name, former address, if changed since last report) No Change Lehman Mortgage Trust 2007-3 7 4 5 S e v e n t h A v e n u e New York, New York 10019 (212) 526-7000 New York

Registered/reporting pursuant to (check one)

Section 15(d)

Name of exchange

Title of Class

Has the registrant (1) filed all reports required to be filed by Section 13 or 15(d) of the Securities and Exchange Act of 1934
during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has
been subject to such filing requirements for the past 90 days?

YES

(If Section 12(b))

PART I - DISTRIBUTION INFORMATION

Item 1. Distribution and Pool Performance Information.

On ~~May~~June 25, 2007 a distribution was made to holders of Lehman Mortgage Trust 2007-3, Mortgage Pass-Through Certificates, Series 2007-3. The monthly report to holders is attached as Exhibit 99.1.

1-A1

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