EXHIBIT 11

            [LETTERHEAD OF SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP]


                                  May 5, 2005



Van Kampen Municipal Trust
1221 Avenue of the Americas
New York, New York  10020

         Re:      Van Kampen Municipal Trust
                  Registration Statement on Form N-14


Ladies and Gentlemen:

         We have acted as special counsel to Van Kampen Municipal Trust, a
voluntary association with transferable shares organized and existing under and
by virtue of the laws of The Commonwealth of Massachusetts (commonly referred to
as a "Massachusetts business trust") (the "Fund"), in connection with the
preparation of the Fund's Registration Statement on Form N-14 (the "Registration
Statement") filed under the Securities Act of 1933, as amended (the "1933 Act"),
with the Securities and Exchange Commission (the "Commission"). The Registration
Statement relates to the registration under the 1933 Act of common shares of
beneficial interest of the Fund, par value $0.01 per share (the "Common
Shares"), and auction preferred shares of the Fund, par value $0.01 per share,
liquidation preference $25,000 per share (the "Preferred Shares"), to be issued
pursuant to an Agreement and Plan of Reorganization (the "Agreement and Plan of
Reorganization") between the Fund, and Van Kampen Investment Grade Municipal
Trust, a Massachusetts business trust (collectively, the "Shares").

         This opinion is delivered in accordance with the requirements of Item
16 of Form N-14 under the 1933 Act.

         In connection with this opinion, we have examined the originals or
copies, certified or otherwise identified to our satisfaction, of (i)
Registration Statement, as filed with the Commission on March 18, 2005 and as it
is proposed to be amended by Pre-Effective Amendment No. 1 to be filed on or
about May 5, 2005, under the 1933 Act, (ii) the Declaration of Trust (the
"Declaration of Trust"), By-Laws and Certificate of Vote of Trustees
Establishing Preferred Shares of the Fund, each as amended to date, (iii) a
specimen certificate representing the Common Shares, (iv) a specimen certificate
representing the Preferred Shares, (v) the resolutions adopted by the Board of
Trustees of the Fund relating to the Agreement and Plan of Reorganization, the
authorization and issuance of the Shares pursuant to the Agreement and Plan of
Reorganization, the filing of the Registration Statement and any amendments or
supplements thereto and related matters, (vi) a draft of the Agreement and Plan
of Reorganization and (vii) such other




documents as we have deemed necessary or appropriate as a basis for the opinions
set forth herein.

         In such examination we have assumed the legal capacity of natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed, photostatic, or other copies
and the authenticity of the originals of such latter documents. As to any facts
material to such opinion which were not independently established, we have
relied on statements or representations of officers and other representatives of
the Fund or others.

         Based upon and subject to the foregoing, we are of the opinion that
when (i) the Registration Statement shall have become effective and (ii) the
issuance of Shares by the Fund pursuant to the Agreement and Plan of
Reorganization has been validly authorized and, assuming certificates therefor
have been duly executed, countersigned, registered and delivered, or the
shareholders' accounts have been duly credited, and the Shares represented
thereby have been fully paid for, such Shares will be validly issued, fully paid
and, subject to the statements set forth below regarding the liability of a
shareholder of a Massachusetts business trust, nonassessable.

         Pursuant to certain decisions of the Supreme Judicial Court of The
Commonwealth of Massachusetts, shareholders of a Massachusetts business trust
may, in certain circumstances, be assessed or held personally liable as partners
for the obligations of a Massachusetts business trust. Even if the Fund were
held to be a partnership, however, the possibility of the holders of Shares
incurring personal liability for financial losses of the Fund appears remote
because (A) Article V, Section 5.1 of the Declaration of Trust contains an
express disclaimer of liability for holders of shares of beneficial interest of
the Fund, including the Shares, for the obligations of the Fund and provides
that the Fund shall hold each holder of such shares harmless from, and shall
indemnify such holder against, all loss and expense arising solely from being or
having been a holder of such shares and (B) Article V, Section 5.5 of the
Declaration of Trust requires that a recitation of such disclaimer be included
in every written obligation, contract, instrument, certificate, share, other
security of the Fund or undertaking made or issued by the trustees of the Fund.

         We hereby consent to the filing of this opinion with the Commission as
Exhibit 11 to the Registration Statement. We also consent to the reference to
our firm under the heading "Legal Matters" in the Registration Statement. In
giving this consent, we do not hereby admit that we are in the category of
persons whose consent is required under Section 7 of the 1933 Act or the rules
and regulations of the Commission.

                                  Very truly yours,

                                  /s/ Skadden, Arps, Slate, Meagher & Flom LLP



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