Exhibit 5.1

[Letterhead of Cadwalader, Wickersham & Taft LLP]

March 20, 2015

Cigna Corporation
900 Cottage Grove Road
Bloomfield, Connecticut  06002

Ladies and Gentlemen:

Cigna Corporation, a Delaware corporation (the “Company”), has filed with the Securities and Exchange Commission (the “Commission”) a Registration Statement on Form S-3 (File No. 333-183238) (the “Registration Statement”) for the purpose of registering under the Securities Act of 1933, as amended (the “Securities Act”), certain securities, including $900,000,000 aggregate principal amount of the Company’s 3.250% Senior Notes due 2025 (the “Notes”).  The Notes are being issued pursuant to the Senior Indenture, dated as of August 16, 2006, by and between the Company and U.S. Bank National Association, as trustee (the “Trustee”), as amended by Supplemental Indenture No. 3 thereto, dated as of March 7, 2008 (as amended, the “Base Indenture”), and as supplemented by Supplemental Indenture No. 9 to the Base Indenture, dated as of March 20, 2015 (the “Supplemental Indenture,” and together with the Base Indenture and any amendments or supplements thereto, the “Indenture”).  The Notes are being offered and sold by the Company pursuant to the terms of the Underwriting Agreement, dated March 11, 2015 (the “Underwriting Agreement”), by and among the Company and J.P. Morgan Securities LLC and Merrill Lynch, Pierce, Fenner & Smith Incorporated, and the other several Underwriters named in Schedule I thereto.  We have acted as special counsel to the Company in connection with the aforementioned transaction.

In rendering the opinions set forth below, we have reviewed such certificates, corporate and public records, agreements and instruments and other documents, including, among other things, the documents delivered on the date hereof, as we have deemed appropriate as a basis for the opinions expressed below.  In all such examinations we have assumed the genuineness of all signatures, the authenticity of all documents, agreements and instruments submitted to us as originals, the conformity to original documents, agreements and instruments of all documents, agreements and instruments submitted to us as copies or specimens, the authenticity of the originals of such documents, agreements and instruments submitted to us as copies or specimens, the conformity of the text of each document filed with the Commission through the Commission’s Electronic Data Gathering, Analysis and Retrieval System to the printed document reviewed by us, the accuracy of the matters set forth in the documents, agreements and instruments we reviewed, and that such documents, agreements and instruments evidence the entire understanding between the parties thereto and have not been amended,

modified or supplemented in any manner material to the opinions expressed herein. As to matters of fact relevant to the opinions expressed herein, we have relied upon, and assumed the accuracy of, the representations and warranties contained in the Underwriting Agreement, and we have relied upon certificates and oral or written statements and other information obtained from the Company, the other parties to the transaction referenced herein, and public officials.  Except as expressly set forth herein, we have not undertaken any independent investigation (including, without limitation, conducting any review, search or investigation of any public files, records or dockets) to determine the existence or absence of the facts that are material to our opinions, and no inference as to our knowledge concerning such facts should be drawn from our reliance on the representations of the Company and others in connection with the preparation and delivery of this letter.

We have also assumed (x) the legal capacity of all natural persons and (y) (except to the extent expressly opined on herein) that all documents, agreements and instruments have been duly authorized, executed and delivered by all parties thereto, that all such parties are validly existing and in good standing under the laws of their respective jurisdictions of organization, that all such parties had the power and legal right to execute and deliver all such documents, agreements and instruments, and that such documents, agreements and instruments constitute the legal, valid and binding obligations of such parties, enforceable against such parties in accordance with their respective terms.

We express no opinion concerning the laws of any jurisdiction other than the laws of the State of New York and, to the extent expressly referred to in this letter, the federal laws of the United States of America, and the General Corporation Law of the State of Delaware, including the applicable provisions of the Delaware Constitution and the reported judicial decisions interpreting such law, in each case as currently in effect.  While we are not licensed to practice law in the State of Delaware, we have reviewed applicable provisions of the Delaware General Corporation Law as we have deemed appropriate in connection with the opinions expressed herein.  Except as described, we have neither examined nor do we express any opinion with respect to Delaware law.

Based upon and subject to the foregoing, we are of the opinion that the Notes have been duly authorized and executed by the Company and, assuming due authentication thereof by the Trustee and upon payment and delivery in accordance with the Underwriting Agreement, will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms and will be validly issued and outstanding and entitled to the benefits of the Indenture, subject to applicable bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium, receivership or other laws relating to or affecting creditors’ rights generally, and to general principles of equity (regardless of whether enforcement is sought in a proceeding at law or in equity), and except that the enforcement of rights with respect to indemnification obligations and provisions purporting to waive or limit rights to trial by jury or oral amendments to written agreements may be limited by applicable law or considerations of public policy.

We hereby consent to the filing of this opinion as an exhibit to a report on Form 8-K filed by the Company on the date hereof and its incorporation by reference into the Registration Statement.  In addition, we consent to the reference to our name under the caption

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“Validity of the Notes” in the prospectus supplement, which is a part of the Registration Statement.  In giving this consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act.  In addition, we disclaim any obligation to update this letter or communicate with or advise you as to any changes in fact or law, or otherwise.

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