GLOBAL BLOOD THERAPEUTICS, INC. 400 EAST JAMIE COURT, SUITE 575 SOUTH SAN FRANCISCO, CA 94080

Exhibit 10.4

GLOBAL BLOOD THERAPEUTICS, INC.

400 EAST JAMIE COURT, SUITE 575

SOUTH SAN FRANCISCO, CA 94080

March 5, 2014

Eleanor L. Ramos, M.D.

Dear Leni,

Global Blood Therapeutics, Inc. (the “Company”) is pleased to offer you employment on the following terms:

1. Position. Your initial title will be Chief Medical Officer and you initially will report to the Company’s Chief Executive Officer. This is a full-time position. While you render services to the Company, you will not engage in any other employment, consulting or other business activity (whether full-time or part-time) that would create a conflict of interest with the Company. By signing this letter agreement, you confirm to the Company that you have no contractual commitments or other legal obligations that would prohibit you from performing your duties for the Company.

2. Cash Compensation. The Company will pay you a starting salary at the rate of $350,000 per year, payable in accordance with the Company’s standard payroll schedule. This salary will be subject to adjustment pursuant to the Company’s employee compensation policies in effect from time to time. In addition to your salary, you will be eligible to participate in the Annual Performance-Based Cash Incentive Award Program. Your benchmark bonus is set at 25 percent of your salary, and the annual payment, if any, will be based on a combination of the achievement of the Company performance goals and your individual performance.

3. Sign-On Bonus. The Company will pay you a sign-on bonus in the amount of $25,000. This will be paid within 30 days of your employment, and will be subject to standard payroll deductions. Should your employment end before one year of service, you will be required to reimburse the Company on a pro-rata basis within 30 days of your separation date.

4. Employee Benefits. As a regular employee of the Company, you will be eligible to participate in a number of Company-sponsored benefits. Should you decide to participate in the Company health benefits program, your coverage will begin the first day of the month following your start date. In addition, you will be entitled to 20 days of paid time off in accordance with the Company’s policy.

5. Stock Options. Subject to the approval of the Company’s Board of Directors or its Compensation Committee, you will be granted an option to purchase 500,000 shares of the Company’s Common Stock. The exercise price per share will be determined by the Board of Directors or the Compensation Committee when the option is granted. The option will be subject to the terms and conditions applicable to options granted under the Company’s 2012 Stock Plan (the “Plan”), as described in the Plan and the applicable stock option agreement. You will vest in 25% of the option shares after 12 months of continuous service, and the balance will vest in equal quarterly installments over the next 36 months of continuous service, as described in the applicable stock option agreement.

6. Relocation Assistance. Global Blood Therapeutics acknowledges that you currently reside in Seattle, Washington, and will need to move your residence to accept this position as full time in the San Francisco Bay Area. The Company will pay you a one-time bonus of $10,000, and it will be subject to customary deductions and withholdings as required by law. Should you voluntarily leave the company within one year of receiving this payment, you will be obligated to return the prorated gross amount of the payment to the Company within 30 days of your separation date.

7. Employee Confidentiality and Assignment Agreement. Like all Company employees, you will be required, as a condition of your employment with the Company, to sign the Company’s standard Employee Confidentiality and Assignment Agreement, a copy of which is attached hereto as Exhibit A.

8. Background Check. The Company may conduct a background or reference check (or both). If so, then you agree to cooperate fully in those procedures, and this offer is subject to the Company’s approving the outcome of those checks, in the discretion of the Company.

9. Employment Relationship. Employment with the Company is for no specific period of time. Your employment with the Company will be “at will,” meaning that either you or the Company may terminate your employment at any time and for any reason, with or without cause. Any contrary representations that may have been made to you are superseded by this letter agreement. This is the full and complete agreement between you and the Company on this term. Although your job duties, title, reporting relationship, compensation and benefits, as well as the Company’s personnel policies and procedures, may change from time to time, the “at will” nature of your employment may only be changed in an express written agreement signed by you and a duly authorized officer of the Company (other than you).

10. Taxes. All forms of compensation referred to in this letter agreement are subject to reduction to reflect applicable withholding and payroll taxes and other deductions required by law. You agree that the Company does not have a duty to design its compensation policies in a manner that minimizes your tax liabilities, and you will not make any claim against the Company or its Board of Directors related to tax liabilities arising from your compensation.

11. Interpretation, Amendment and Enforcement. This letter agreement and Exhibit A constitute the complete agreement between you and the Company, contain all of the terms of your employment with the Company and supersede any prior agreements, representations or understandings (whether written, oral or implied) between you and the Company. This letter agreement may not be amended or modified, except by an express written agreement signed by both you and a duly authorized officer of the Company. The terms of this letter agreement and the resolution of any disputes as to the meaning, effect, performance or validity of this letter agreement or arising out of, related to, or in any way connected with, this letter agreement, your employment with the Company or any other relationship between you and the Company will be governed by California law, excluding laws relating to conflicts or choice of law.

* * * * *

We hope that you will accept our offer to join the Company. You may indicate your agreement with these terms and accept this offer by signing and dating both the enclosed duplicate original of this letter agreement and the enclosed Proprietary Information and Inventions Agreement and returning them to me. This offer, if not accepted, will expire at the close of business on March 10, 2014. As required by law, your employment with the Company is contingent upon your providing legal proof of your identity and authorization to work in the United States. Your employment is also contingent upon your starting work with the Company on or before May 12, 2014.

If you have any questions, please call me at ###-###-####.

I have read and accept this employment offer:

Attachment

Exhibit A: Employee Confidentiality and Assignment Agreement

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