Registration Statement on Form S-8 Filed with SEC

GI Dynamics, Inc. ASX Announcement Registration Statement on Form S-8 Filed with SEC LEXINGTON, Massachusetts, United States and SYDNEY, Australia 18 May 2015 GI Dynamics, Inc. (ASX: GID) ( GI Dynamics or the Company ), a medical device company developing innovative treatments for type 2 diabetes and obesity, announces that it has filed the attached Registration Statement on Form S-8 with the U.S. Securities and Exchange Commission for registration of securities issued or issuable under the Company s 2011 Employee, Director and Consultant Equity Incentive Plan. Robert Solomon Vice President, Finance & Company Secretary About GI Dynamics GI Dynamics, Inc. (ASX: GID) is the developer of EndoBarrier, the first endoscopically-delivered device therapy approved for the treatment of obese type 2 diabetes with BMI 30 kg/m 2, or obese patients with BMI 30 kg/m 2 with 1 comorbidities, or obese patients with BMI >35 kg/m 2. The liner is indicated for a maximum implant duration of 12 months. EndoBarrier is approved and commercially available in multiple countries outside the U.S. EndoBarrier is not approved for sale in the U.S. and is limited by federal law to investigational use only in the United States. GI Dynamics is conducting a pivotal clinical trial of EndoBarrier in the U.S. for the treatment of patients who have uncontrolled type 2 diabetes and are obese. Founded in 2003, GI Dynamics is headquartered in Lexington, Massachusetts. For more information, please visit www.gidynamics.com. Forward-Looking Statements This announcement contains forward-looking statements concerning: our development and commercialization plans; our potential revenues and revenue growth, costs, excess inventory, profitability and financial performance; our ability to obtain reimbursement for our products; our clinical trials, and associated regulatory submissions and approvals; the number and location of commercial centres offering the EndoBarrier ; and our intellectual property position. These forward-looking statements are based on the current estimates and expectations of future events by the management of GI Dynamics, Inc. as of the date of this announcement and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those indicated in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks associated with the possibility that clinical trials will not be successful or confirm earlier results; risks associated with obtaining funding from third parties; risks relating to the timing and costs of clinical trials, the timing of regulatory submissions, the timing, receipt and maintenance of regulatory approvals, the timing and amount of other expenses, and the timing and extent of third-party reimbursement; risks associated with commercial product sales, including product performance; competition; risks related to market acceptance of products; intellectual property risks; risks related to excess inventory; risks related to assumptions regarding the size of the available market, benefits of our products, product pricing, timing of product launches, future financial results and other factors including those described in our filings with the U.S. Securities and Exchange Commission. Given these uncertainties, you should not place undue reliance on these forwardlooking statements. We do not assume any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, unless required by law. www.gidynamics.com US OFFICE & HEADQUARTERS: 25 Hartwell Avenue, Lexington MA 02421 T +1 (781) 357-3300 F +1 (781) 357-3301 EUROPEAN OFFICE: Prinzenallee 7, 40549 Dusseldorf, Germany T: +49 211 5239 1572 AUSTRALIAN OFFICE: Level 8, 17-19 Bridge Street, Sydney, NSW 2000 T +61 2 9325 9046 GI Dynamics, Inc., is a corporation incorporated in Delaware, USA, whose stockholders have limited liability. ARBN 151 239 388

GI Dynamics, Inc. - ASX Announcement Page 2 Investor Enquiries: United States Michael Dale, President & CEO +1 (781) 357-3310 Media Enquiries: United States/Europe: Bill Berry, Berry & Company Public Relations, LLC +1 (212) 253-8881 Australia David Allen or John Granger Hawkesbury Partners Pty Limited +61 2 9325 9046 www.gidynamics.com US OFFICE & HEADQUARTERS: 25 Hartwell Avenue, Lexington MA 02421 T +1 (781) 357-3300 F +1 (781) 357-3301 EUROPEAN OFFICE: Prinzenallee 7, 40549 Dusseldorf, Germany T: +49 211 5239 1572 AUSTRALIAN OFFICE: Level 8, 17-19 Bridge Street, Sydney, NSW 2000 T +61 2 9325 9046 GI Dynamics, Inc., is a corporation incorporated in Delaware, USA, whose stockholders have limited liability. ARBN 151 239 388

As filed with the Securities and Exchange Commission on May 15, 2015 Registration No. 333 - UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 GI DYNAMICS, INC. (Exact name of registrant as specified in its charter) Delaware 84-1621425 (State or other jurisdiction of incorporation or organization) 25 Hartwell Avenue Lexington, Massachusetts 02421 (Address of Principal Executive Offices) (Zip Code) 2011 EMPLOYEE, DIRECTOR AND CONSULTANT EQUITY INCENTIVE PLAN (Full title of the plan) Michael D. Dale Chief Executive Officer 25 Hartwell Avenue Lexington, Massachusetts 02421 (781) 357-3300 (Name and address of agent for service) (Telephone number, including area code, of agent for service) (I.R.S. Employer Identification No.) Copies to Daniel H. Follansbee, Esq. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. One Financial Center Boston, MA 02111 Telephone (617) 542-6000 Facsimile (617) 542-2241 Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See definition of accelerated filer, large accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act. Check one:

Large accelerated filer Accelerated filer Non-accelerated filer (Do not check if smaller reporting company) Smaller reporting company Title of securities to be registered CALCULATION OF REGISTRATION FEE Amount to be registered (1) Proposed maximum offering price per share Proposed maximum aggregate offering price Amount of registration fee Common Stock, $0.01 par value 353,389 (2) $4.46 (3) $1,576,114.94 $183.15 Common Stock, $0.01 par value 25,957 (4) $5.38 (5) $139,648.66 $16.23 Total 379,346 $1,715,763.60 $199.38 (1) In addition, pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the Securities Act ), this Registration Statement also covers such indeterminate number of additional shares of common stock, par value $0.01 per share ( Common Stock ) as is necessary to eliminate any dilutive effect of any future stock split, stock dividend or similar transaction. (2) Consists of shares of Common Stock previously authorized for issuance under the 2011 Employee, Director and Consultant Equity Incentive Plan (the Plan ) on January 1, 2015, in connection with an evergreen provision contained in the Plan (the Evergreen Increase ) for which equity awards have not been granted. (3) This calculation is made solely for the purpose of determining the registration fee pursuant to the provisions of Rules 457(c) and 457(h) under the Securities Act. The price per share and aggregate offering price are calculated on the basis of the average of the high and low sale prices per share of the Common Stock (traded as fifty CHESS Depositary Interests ( CDIs )) on the Australian Securities Exchange (the ASX ) as of a date (May 12, 2015) within 5 business days prior to filing this Registration Statement. The price of the Common Stock is calculated as the closing price of the CDIs as reported on the ASX multiplied by 50 (to account for the 1:50 ratio of Common Stock to CDIs) and then multiplied by the exchange rate reported by the Reserve Bank of Australia for that day. (4) Consists of shares of Common Stock of the Registrant issuable upon exercise of stock options granted under the Plan from the Evergreen Increase to certain employees of the Registrant on April 10, 2015. (5) Solely for the purposes of determining the registration fee under Rule 457(h) promulgated under the Securities Act, this price is equal to the per share exercise price of these stock options granted under the Plan.

EXPLANATORY NOTE This Registration Statement registers additional securities under the Plan pursuant to the Evergreen Increase of the same class as other securities for which the registration statement filed on Form S-8 (SEC File No. 333-200150) of the Registrant is effective. The information contained in the Registrant s registration statement on Form S-8 (SEC File No. 333-200150) is hereby incorporated by reference pursuant to General Instruction E of Form S-8.

PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT Item 8. Exhibits. The Exhibit Index immediately preceding the exhibits is incorporated herein by reference. -1-

SIGNATURES Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Lexington, Commonwealth of Massachusetts, on this 15th day of May, 2015. GI DYNAMICS, INC. By: /s/ Robert M. Solomon Robert M. Solomon Vice President, Finance, Treasurer and Secretary Each person whose signature appears below constitutes and appoints Michael D. Dale and Robert M. Solomon, and each of them singly, his/her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution in each of them singly, for him/her and in his/her name, place and stead, and in any and all capacities, to sign any and all amendments (including posteffective amendments) to this Registration Statement on Form S-8 of GI Dynamics, Inc., and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting to the attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in or about the premises, as fully to all intents and purposes as he/she might or could do in person, hereby ratifying and confirming all that the attorneys-in-fact and agents or any of each of them or their substitute may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated. Signature Title Date /s/ Michael D. Dale Michael D. Dale /s/ Robert M. Solomon Robert M. Solomon President, Chief Executive Officer and Executive Director (principal executive officer) Vice President, Finance, Treasurer and Secretary (principal financial and accounting officer) May 15, 2015 May 15, 2015 /s/ Jack E. Meyer Chairman of the Board of Directors May 15, 2015 Jack E. Meyer /s/ Timothy J. Barberich Director May 15, 2015 Timothy J. Barberich /s/ Graham J. Bradley Director May 15, 2015 Graham J. Bradley /s/ Michael A. Carusi Director May 15, 2015 Michael A. Carusi /s/ Anne J. Keating Director May 15, 2015 Anne J. Keating /s/ Daniel J. Moore Director May 15, 2015 Daniel J. Moore

INDEX TO EXHIBITS Exhibit Number Description 5.1* Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as to the legality of shares being registered 23.1* Consent of Independent Registered Public Accounting Firm (Ernst & Young LLP) 23.2* Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (included in opinion of counsel filed as Exhibit 5.1) 24.1 Powers of Attorney to file future amendments (set forth on the signature page of this registration statement) * filed herewith

Exhibit 5.1 One Financial Center Boston, MA 02111 617-542-6000 617-542-2241 fax www.mintz.com May 15, 2015 GI Dynamics, Inc. 25 Hartwell, Ave. Lexington, MA 02421 Ladies and Gentlemen: We have acted as legal counsel to GI Dynamics, Inc. a Delaware corporation (the Company ), in connection with the preparation and filing with the Securities and Exchange Commission (the Commission ) of a Registration Statement on Form S-8 (the Registration Statement ), pursuant to which the Company is registering the issuance under the Securities Act of 1933, as amended (the Securities Act ), of an aggregate of 379,346 shares (the Shares ) of the Company s common stock, $.01 par value per share (the Common Stock ), issued or issuable pursuant to the Company s 2011 Employee, Director and Consultant Equity Incentive Plan (the Plan ). This opinion is being rendered in connection with the filing of the Registration Statement with the Commission. All capitalized terms used herein and not otherwise defined shall have the respective meanings given to them in the Registration Statement. In connection with this opinion, we have examined the Company s Restated Certificate of Incorporation and Restated By-Laws, both as currently in effect; such other records of the corporate proceedings of the Company and certificates of the Company s officers as we have deemed relevant; and the Registration Statement and the exhibits thereto. In our examination, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as certified or photostatic copies and the authenticity of the originals of such copies. In addition, we have assumed that the Company will receive any required consideration in accordance with the terms of the Plan. Our opinion is limited to the General Corporation Law of the State of Delaware and we express no opinion with respect to the laws of any other jurisdiction. No opinion is expressed herein with respect to the qualification of the Shares or the rights under the securities or blue sky laws of any state or any foreign jurisdiction. Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters. This opinion is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. BOSTON LONDON LOS ANGELES NEW YORK SAN DIEGO SAN FRANCISCO STAMFORD WASHINGTON

Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. May 15, 2015 Page 2 Based upon the foregoing, we are of the opinion that the Shares, when issued and delivered in accordance with the terms of the Plan, will be validly issued, fully paid and non-assessable. We understand that you wish to file this opinion with the Commission as an exhibit to the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K promulgated under the Securities Act, and we hereby consent thereto. In giving this consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder. Very truly yours, /s/ Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

Exhibit 23.1 Consent of Independent Registered Public Accounting Firm We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the 2011 Employee, Director and Consultant Equity Incentive Plan of GI Dynamics, Inc. of our report dated March 30, 2015 with respect to the consolidated financial statements of GI Dynamics, Inc. and Subsidiaries included in its Annual Report (Form 10-K) for the year ended December 31, 2014, filed with the Securities and Exchange Commission. /s/ Ernst & Young LLP Boston, Massachusetts May 15, 2015