[BFA Letterhead]
August 23, 2012
Securities and Exchange Commission
100 F Street, N.E.
Washington, DC 20549
| RE: | iShares U.S. ETF Trust |
| (Securities Act File No. 333-179904; |
| Investment Company Act File No. 811-22649) |
| Amendment No. 1 |
Ladies and Gentlemen:
Pursuant to Rule 461 under the Securities Act of 1933, as amended, iShares U.S. ETF Trust (the “Registrant”) hereby respectfully requests acceleration of its Registration Statement on Form N-1A, relating to the iShares Ultrashort Duration Bond Fund (the “Fund”), a series of the Registrant, so that it will become effective on September 4, 2012, or as soon thereafter as practicable.
We request that we be notified of such effectiveness by a telephone call to Benjamin Haskin of Willkie Farr & Gallagher LLP at (202) 303-1124.
The Registrant hereby acknowledges that, if the Securities and Exchange Commission (or its staff, acting pursuant to delegated authority) (the “Commission”) declares the filing effective, such action:
| (i) | does not foreclose the Commission from taking any action with respect to the filing; |
| (ii) | does not relieve the Registrant from its full responsibility for the adequacy and accuracy of the disclosure in the filing; and |
| (iii) | may not be asserted by the Registrant as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States. |
Very Truly Yours,
iShares U.S. ETF Trust
| By: | /s/ Jack Gee | |
Jack Gee Treasurer and Chief Financial Officer | ||
BlackRock Investments, LLC
| By: | /s/ Stephen Hart | |
Stephen Hart Secretary | ||
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