Clean Diesel Technologies, Inc. Announces Pricing of Public Offering

VENTURA, California, June 29, 2011 -

Clean Diesel Technologies, Inc. (NASDAQ: CDTI) (”Clean Diesel”),
a cleantech emissions reduction company, today announced the
pricing of an underwritten public offering of 2,725,000 shares of
its common stock at a price to the public of $3.75 per share.
2,645,000 of these shares are being offered by Clean Diesel and
80,000 of these shares are being offered by selling stockholders.
Clean Diesel has granted a 30-day option to the underwriters to
purchase up to an additional 408,750 shares of common stock to
cover over-allotments. Subject to the satisfaction of customary
conditions, the offering is expected to close on or about July 5,
2011.

Roth Capital Partners is acting as sole book-runner for the
offering with Maxim Group, LLC acting as a co-manager.

Clean Diesel intends to use the net proceeds from this public
offering primarily for working capital and general corporate
purposes. Clean Diesel will not receive any proceeds from shares
sold by the selling stockholders.

This press release shall not constitute an offer to sell or the
solicitation of an offer to buy, nor shall there be any sale of,
the common stock in any jurisdiction in which such offer,
solicitation or sale would be unlawful prior to registration or
qualification under the securities laws of any such
jurisdiction.

A copy of the prospectus relating to these securities may be
obtained, when available, by contacting Roth Capital Partners,
Attention: Equity Capital Markets, 24 Corporate Plaza Drive,
Newport Beach, CA 92660, by telephone at (800) 678-9147, or via
email at href="mailto:rothecm@roth.com">rothecm@roth.com.

About Clean Diesel Technologies, Inc.

Clean Diesel is a vertically integrated global manufacturer and
distributor of emissions control systems and products, focused on
the heavy duty diesel and light duty vehicle markets. Clean Diesel
utilizes its proprietary patented Mixed Phase Catalyst (MPC®)
technology, as well as its ARIS® selective catalytic reduction,
Platinum Plus® fuel-borne catalyst, and other technologies to
provide high-value sustainable solutions to reduce emissions,
increase energy efficiency and lower the carbon intensity of on-
and off-road engine applications. Clean Diesel is headquartered in
Ventura, California and currently has operations in the U.S.,
Canada, U.K., France, Japan and Sweden. For more information,
please visit href="www.cdti.com/">www.cdti.com.

Forward-Looking Statements Safe Harbor

Certain statements in this news release, such as the expected
closing date of the offering and the use of proceeds, constitute
“forward-looking statements” within the meaning of the Private
Securities Litigation Reform Act of 1995. Such forward-looking
statements involve known or unknown risks, including those detailed
in Clean Diesel’s filings with the U.S. Securities and Exchange
Commission, uncertainties and other factors that may cause the
actual results, performance or achievements of Clean Diesel to be
materially different from any future results, performance or
achievements expressed or implied by such forward-looking
statements. Readers are cautioned not to place undue reliance on
these forward-looking statements, which speak only as of the date
hereof. Clean Diesel assumes no obligation to update the
forward-looking information contained in this release.

Kristi Cushing, Investor Relations Manager, +1-805-639-9458