Y-MABS THERAPEUTICS, INC.

230 Park Avenue, Suite 3350

New York, NY 10169

VIA EDGAR

Ms. Ada D. Sarmento

Office of Life Sciences

United States Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Dear Ms. Sarmento:

Pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), Y-mAbs Therapeutics, Inc. (the “Company”), hereby respectfully requests that the effective date of the above-referenced registration statement (the “Registration Statement”) be accelerated to October 15, 2019, at 4:30 p.m. Eastern Time, or as soon thereafter as practicable, unless we or our outside counsel, Satterlee Stephens LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this acceleration request, the Company acknowledges that it is aware of its responsibilities under the Act.

If you have any questions regarding this request, please contact Dwight A. Kinsey, Esq., at (212) 404-8727, or in his absence, Rina R. Patel, Esq., at (212) 404-8736, both of Satterlee Stephens LLP. Thank you for your assistance and cooperation in this matter.