SecProbe.io

Mail Stop 3561

 May 10, 2007

Andrew J. Littlefair
President and Chief Executive Officer
Clean Energy Fuels Corp.
3020 Old Ranch Parkway, Suite 200
Seal Beach, California  90740

Re: Clean Energy Fuels Corp.
Amendment No. 3 to Registrati on Statement on Form S-1
Filed May 9, 2007
File No. 333-137124

Dear Mr. Littlefair:

We have reviewed your filing and have the following comments.  Where
indicated, we think you should re vise your document in response to these comments.  If
you disagree, we will consider your explanation as to why our comment is inapplicable or
a revision is unnecessary.  Please be as deta iled as necessary in your explanation.  In
some of our comments, we may ask you to provi de us with information so we may better
understand your disclosure.  After reviewing th is information, we may raise additional
comments.

Plan of Distribution, page 109
1. We note your response to comment 4 in our letter dated May 8, 2007.  In light of
the analysis you have provided, in an a ppropriate place in your registration
statement, please disclose that the sel ling stockholders may be deemed to be
underwriters within the mean ing of Section 2(11) of th e Securities Act, and any
discount, commission, or concession receiv ed by them and any provided by the
sale of the shares by them may be d eemed to be underwriting discounts and
commissions under the Securities Act.

Note (5) Stockholders’ Equity, page F-15

(c) Exercise of Warrants; Equity Option Agreements, page F-17
2. We note your response to comment 7 in our letter dated May 8, 2007.  In light of
your need to raise capital quickly, please explain to us why there was a significant

Andrew J. Littlefair
Clean Energy Fuels Corp.
May 10, 2007  Page 2
time lag between the January 2006 capital call and final cash receipt in April 2006.  We would expect the major benefit of the agreement to be immediate access to cash.  Additionally, please tell us whether you had access to other capital raising opportunities at  the time of the capital call and tell us what, if any,
consideration was given to outside financi ng as well as why such options were not
pursued.  If other avenues were available, please explain to us  in greater detail
why you opted to issue stock below market value.  In this regard, we note the
opportunity cost of exercising the put when  the market value was higher than the
strike price was significant.  Accordingly, please be deta iled in your response.

Note (10) Related Party Transactions, page F-24
3. We note your response to comment 8 in our letter dated May 8, 2007.  Although it
is appropriate to use the expected term  in calculating the fair value of an
employee  stock option, please explain to us how you concluded it was appropriate
to use the expected term, rather than th e contractual maturity, in calculating the
fair value of the warrant issued to Boone  Pickens.  It appears from Exhibit 10.26
that such warrant is transferable with the consent of the company.  If you believe
expected term is the appropriate input variable, please explain to us why Mr. Pickens’s request to extend the warrant term to 10 years supports a 4-year
expected term, as opposed to a longer pe riod.  Finally, please explain to us in
further detail why you believe the market  price of your common stock remained
unchanged through the majority of 2006 but increased dramatically in early 2007.
For example, please explain to us wh y the January 2006 State of the Union
Address resulted in an increase in stoc k value in 2007 but not in 2006.  You may
want to provide us with a more define d timeline of events and associate each
event with some quantification of the ma gnitude of fair value increase.  For
instance, please show us more specifica lly the periods over which the increase in
the spread between oil and na tural gas prices occurred.

* * * * * *

As appropriate, please amend your regist ration statement in response to these
comments.  You may wish to provide us with marked copies of the amendment to expedite our review.  Please furnish a cove r letter with your amendment that keys your
responses to our comments and provides any requested information.  Detailed cover
letters greatly facilitate our review.  Please understand that we may have additional comments after reviewing your amendmen t and responses to our comments.

You may contact Sarah Goldberg, Staff Accountant, at (202) 551-3340 or James
Allegretto, Senior Assistant Chief Accountan t, at (202) 551-3849, if  you have questions
regarding comments on the financ ial statements and related ma tters.  Please contact John

Andrew J. Littlefair
Clean Energy Fuels Corp.
May 10, 2007  Page 3
Fieldsend, Staff Attorney, at (202) 551-3343 or me at (202) 551-3720 with any other
questions.

Sincerely,

H. Christopher Owings
Assistant Director

cc: John J. Hentrich, Esq.
 Sheppard, Mullin, Richter & Hampton LLP
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