| Delaware | 000-51222 | 33-0857544 | 
| (State or other jurisdiction of incorporation) | (Commission File Number) | (I.R.S. Employer Identification Number) | 
| 6340 Sequence Drive, San Diego, CA | 92121     | ||
| (Address of principal executive offices) | (Zip Code) | ||
| (858) 200-0200 | ||
| (Registrant’s telephone number, including area code) | ||
| Amended and Restated 2015 Equity Incentive Plan  | ||
| (Full Title of the Plans)  | ||
| Robert A. Freedman, Esq.  Michael A. Brown, Esq.  Fenwick & West LLP  801 California Street  Mountain View, CA 94041  (650) 988-8500  | Patrick Murphy General Counsel and Chief Compliance Officer c/o DexCom, Inc.  6340 Sequence Drive  San Diego, California 92121  (858) 200-0200  | 
| Large accelerated Filer | x | Accelerated Filer | ☐ | |||
| Non-accelerated Filer | ☐ | Smaller reporting company | ☐ | |||
| Emerging growth company | ☐ | |||||
| CALCULATION OF REGISTRATION FEE   | |||||||||
| Title of Each Class of Securities to be Registered | Amount to be Registered(1) | Proposed Maximum Offering Price Per Share | Proposed Maximum Aggregate Offering Price | Amount of Registration Fee | |||||
| Common Stock, $0.001 par value | 2,200,000(2) | $154.76(3) | $340,472,000(3) | $44,193 | |||||
| Total | 2,200,000 | $340,472,000 | $44,193 | ||||||
| (1) | Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the “Securities Act”), this Registration Statement shall also cover any additional shares of the Registrant’s common stock that become issuable under the Amended and Restated 2015 Equity Incentive Plan, as amended to date (the “2015 Plan”) by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without the receipt of consideration that increases the number of the Registrant’s outstanding shares of common stock.  | ||||||||
| (2) | Represents 2,200,000 additional shares of common reserved for issuance upon the exercise of stock options and the settlement of restricted stock unit awards under the 2015 Plan to be granted by the Registrant. Shares available for issuance under the 2015 Plan were previously registered on a Registration Statement on Form S-8 filed with the Securities and Exchange Commission (the “Commission”) on June 3, 2015 (File No. 333-204699) and on a Registration Statement on Form S-8 filed with the Commission on June 7, 2017 (File No. 333-218562). | 
| (3) | Estimated pursuant to Rule 457(c) and (h) of the Securities Act, solely for purposes of calculating the registration fee, based on the average of the high and low sales price reported on the Nasdaq Global Select Market on November 6, 2019. | 
| Incorporated by Reference | ||||||||||||
| Exhibit Number | Exhibit Document | Form | File No. | Date of First Filing | Exhibit Number | Provided Herewith | ||||||
| X | ||||||||||||
| X | ||||||||||||
| 23.02 | Consent of Fenwick & West LLP (included in Exhibit 5.01). | X | ||||||||||
| 24.01 | Power of Attorney (see signature page). | X | ||||||||||
| DEXCOM, INC. | ||
| By: | /s/ Kevin Sayer | |
| Kevin Sayer Chairman, President and Chief Executive Officer  | ||
| Signature | Capacity | Date | |||||
| /S/    KEVIN R. SAYER | Chairman of the Board of Directors, President and Chief Executive Officer (Principal Executive Officer) | November 13, 2019 | |||||
| Kevin R. Sayer | |||||||
| /S/    QUENTIN S. BLACKFORD | Chief Operating Officer and Chief Financial Officer (Principal Financial and Accounting Officer) | November 13, 2019 | |||||
| Quentin S. Blackford | |||||||
| /S/    MARK FOLETTA | Lead Independent Director | November 13, 2019 | |||||
| Mark Foletta | |||||||
| /S/    STEVE ALTMAN | Director | November 13, 2019 | |||||
| Steve Altman | |||||||
| Director | |||||||
| Nicholas Augustinos | |||||||
| /S/    RICHARD COLLINS | Director | November 13, 2019 | |||||
| Richard Collins | |||||||
| /S/    BRIDGETTE HELLER | Director | November 13, 2019 | |||||
| Bridgette Heller | |||||||
| /S/    BARBARA KAHN | Director | November 13, 2019 | |||||
| Barbara Kahn | |||||||
| /S/    JAY SKYLER | Director | November 13, 2019 | |||||
| Jay Skyler, M.D. | |||||||
| /S/    ERIC TOPOL | Director | November 13, 2019 | |||||
| Eric Topol, M.D. | |||||||