EX-99.3

Offer to Exchange up to $300,000,000 Floating Rate Senior Notes due 2017 for a Like Principal Amount of Floating Rate Senior Notes due 2017 which have been registered under the Securities Act of 1933 (the “2017 Notes Exchange Offer”);

Offer to Exchange up to $400,000,000 4.250% Senior Notes due 2024 for a Like Principal Amount of 4.250% Senior Notes due 2024 which have been registered under the Securities Act of 1933 (the “2024 Notes Exchange Offer” and, together with the 2017 Notes Exchange Offer, the “exchange offers” and each an “exchange offer”).

Martin Marietta Materials, Inc., a North Carolina corporation (the “Company”), hereby offers to exchange, upon and subject to the terms and conditions set forth in the prospectus dated , 2014 (the “Prospectus”) and the related letter of transmittal (the “Letter of Transmittal”), up to $300,000,000 aggregate principal amount of its outstanding, unregistered Floating Rate Senior Notes due 2017 (the “Original 2017 Notes”) for an equivalent amount of registered Floating Rate Senior Notes due 2017 (the “Exchange 2017 Notes”) and up to $400,000,000 aggregate principal amount of its outstanding, unregistered 4.250% Senior Notes due 2024 (the “Original 2024 Notes” and, together with the Original 2017 Notes, the “Original Notes” and each an “Original Note”) for an equivalent amount of registered 4.250% Senior Notes due 2024 (the “Exchange 2024 Notes” and, together with the Exchange 2017 Notes, the “Exchange Notes” and each an “Exchange Note”). The Original Notes and the Exchange Notes are sometimes referred to in this letter together as the “Notes.” Capitalized terms not defined herein shall have the meaning ascribed to them in the Prospectus.

The exchange offers are intended to satisfy certain obligations of the Company contained in the Registration Rights Agreement, dated as of July 2, 2014, among Martin Marietta Materials, Inc. and Deutsche Bank Securities Inc. and J.P. Morgan Securities LLC, as representatives of the several Initial Purchasers, relating to the Original 2017 Notes and the Original 2024 Notes. As set forth in the Prospectus, the terms of the Exchange Notes are substantially identical to the terms of the corresponding series of the Original Notes, except that the Exchange Notes are registered under the Securities Act of 1933 and the transfer restrictions, registration rights and payment of additional interest in case of non-registration applicable to the Original Notes do not apply to the Exchange Notes.

Please contact your clients for whom you hold Original Notes regarding the exchange offers. For your information and for forwarding to your clients for whom you hold Original Notes registered in your name or in the name of your nominee, or who hold Original Notes registered in their own names, the following documents are enclosed:

Your prompt action is requested. The exchange offers will expire at 5:00 p.m., New York City time, on , 2014, subject to the Company’s right to extend the expiration date for any exchange offer (such date and time, the “Expiration Date”). Any Original Notes tendered pursuant to the exchange offers may be withdrawn at any time prior to the Expiration Date.

The Company will, upon request, reimburse brokers, dealers, commercial banks and trust companies for reasonable and necessary costs and expenses incurred by them in forwarding the Prospectus and related documents to the beneficial owners of the Original Notes held by them as nominee or in a fiduciary capacity. The Company has not retained any dealer-manager in connection with the exchange offers and will not make any payment to brokers, dealers or others soliciting acceptances of the exchange offers.

To participate in the exchange offers, a duly executed and properly completed Letter of Transmittal (or facsimile thereof), with any required signature guarantees, and any other documents required by the Letter of Transmittal or an Agent’s Message (as defined in the Letter of Transmittal) stating that the tendering holder has expressly acknowledged receipt of, and agrees to be bound by and held accountable under, the Letter of Transmittal, must be sent to the Exchange Agent and certificates representing the Original Notes (or confirmation of book-entry transfer of such Original Notes into the Exchange Agent’s account at The Depository Trust Company) must be delivered to the Exchange Agent, all in accordance with the instructions set forth in the Letter of Transmittal and the Prospectus.

Any inquiries you may have with respect to the exchange offers or requests for additional copies of the enclosed materials should be directed to the Exchange Agent at its address and telephone number set forth on the front of the Letter of Transmittal.

NOTHING HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU OR ANY OTHER PERSON AS AN AGENT OF THE COMPANY OR THE EXCHANGE AGENT, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY STATEMENTS ON BEHALF OF ANY OF THEM WITH RESPECT TO THE EXCHANGE OFFERS, EXCEPT FOR STATEMENTS EXPRESSLY MADE IN THE PROSPECTUS OR THE LETTER OF TRANSMITTAL.