SecProbe.io

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549-7010

       DIVISION OF
CORPORATION FINANCE

Mail Stop 7010

May 16, 2006

Mr. David P. Steiner
Chief Executive Officer
Waste Management, Inc.
1001 Fannin Street, Suite 4000
Houston, TX  77002

RE: Waste Management, Inc.
Form 10-K for Fiscal Year Ended December 31, 2005
  Filed February 21, 2006
File No. 001-12154

Dear Mr. Steiner:

  We have limited our review of your fili ng to those issues we have addressed in
our comments.  If you disagree with a comment,  we will consider your explanation as to
why our comment is inapplicable or a revisi on is unnecessary.  Please be as detailed as
necessary in your explanation.  In some of our comments, we may ask you to provide us
with supplemental information so we may better understand your disclosure.  After reviewing this information, we may or  may not raise additional comments.

 Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our comments or on any other aspect of our review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Tax Matters

1. We note that the settlement of tax audits resulted in a reduction in income tax expense of $398 million in 2005, $101 m illion in 2004 and $6 million in 2003.
Were it not for the reversals of the reserves you established for these tax
exposures your net income in 2005 would have fallen 6% rather than increased
26%, as reported. In order for us to  better understand these reserves please
provide us with the following:

Mr. David P. Steiner
Waste Management, Inc.
May 16, 2006 Page 2
- Explain the underlying material tax position(s) you have taken which you
believe may be challenged a nd potentially disallowed;
- Tell us whether you consider the positions  to be specific tax “shelters” as
defined by tax authorities, or whether th ey represent tax uncertainties entered
into in the ordinary course of business;
- Describe the uncertainties surrounding such position(s) and what factors
would impact whether they would be potentially disallowed;
- Quantify in all respects the surround ing accounting for such tax positions;
- Quantify the activity of the reserves from inception, or at least provide
adequate historical perspective concerning the last three years reversals and
their original reserve dates;
- Identify where, in both the income statement and balance sheet, the reserve activity was originally recorded;
- Quantify and identify any current re serves and their underlying purpose;
- Regarding any current reserves, descri be the uncertainties surrounding such
position(s) and what factors would impact whether they would be potentially disallowed
- Indicate in the activity any actual disallowances;

2. In addition, please elaborate on your accounting policy for how you account for
this reserve. For example you state that you record the amounts for positions that
“may be challenged and potentially disallowed ”.  It is unclear from this language
what your overall threshold of probability is when establishing and adjusting this reserve.

3. In light of the material amount of revers als from the reserves, please describe for
us the reasons for the lack of disallo wance and tell us what consideration you
have given to your track r ecord regarding the likelihood of disallowance.  We
may have further comment.

4. Please provide for us an analysis of  your views concerning the FASB May 10,
2006 meeting concerning new disclosure s about tax uncertainties and what
changes you are contemplating to provide more transparency to this material
policy.  Also, tell us what considerati on you have given to including this as a
critical accounting estimate a nd assumption in your MD&A.

*    *    *    *

  Please respond to these comments with in 10 business days, or tell us when you
will provide us with a response.  Please pr ovide us with a supplemental response letter
that keys your responses to our comment s and provides any requested supplemental
information.  Detailed letters greatly facilitate our review.  Please file your supplemental

Mr. David P. Steiner
Waste Management, Inc.
May 16, 2006 Page 3
response on EDGAR as a correspondence file .  Please understand that we may have
additional comments after reviewin g your responses to our comments.

We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filings reviewed by the staff to be certain that they have provided all information investors require for an info rmed decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

 In connection with responding to our comments, please provide, in writing, a statement from the company acknowledging that:

• the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;

• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and

• the company may not assert staff comme nts as a defense in any proceeding
initiated by the Commission or any person under the federal secu rities laws of the
United States.

  In addition, please be advi sed that the Division of En forcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comments on your filing.

If you have any questions regarding these comments, please direct them to Ryan
Rohn, Staff Accountant, at (202)  551-3739 or, in his absence, to the undersigned at (202)
551-3689.

       S i n c e r e l y ,

       John Hartz
       Senior Assistant Chief Accountant