Consent of Independent Certified Public Accountants
We have issued our report dated August 18, 2000 accompanying the financial
statements of Van Kampen Focus Portfolios Trust, Series 166 as of June 30, 2000,
and for the period then ended, contained in this Post-Effective Amendment No. 1
to Form S-6.
We consent to the use of the aforementioned report in the Post-Effective
Amendment and to the use of our name as it appears under the caption "Auditors".
Grant Thornton LLP
Chicago, Illinois
October 25, 2000
