Mail Stop 4-6

May 6, 2005

Mr. Joseph T. Ruble, Esq.
General Counsel and Corporate Secretary
CSG Systems International, Inc.
7887 East Belleview, Suite 1000
Englewood, Colorado 80111

Re:	CSG Systems International, Inc.
	Post-effective Amendment No. 3 to Registration Statement on
Form
S-3
	File No. 333-117427

Dear Mr. Ruble:

      This is to advise you that we have limited our review of the
above registration statement to the matters addressed in the
comments
below.  Where indicated, we think you should revise 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 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 review 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.

Form 10-K for the fiscal year ended December 31, 2004

Item 9A. Controls and Procedures

1. We note your disclosure that "there have been no significant
changes in internal controls over financial reporting."  Please
note
that Item 308 of Regulation S-K requires the disclosure of "any"
change in your internal controls that occurred during your last
fiscal quarter that has materially affected, or is reasonably
likely
to materially affect, your internal controls.  In light of the
foregoing, please supplementally advise us with respect to changes
in
your internal controls during the quarter ended December 31, 2004.


*              *              *              *

      As appropriate, please amend your registration 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
cover letter with your amendment that keys your responses to our
comments and provides any requested supplemental information.
Detailed cover letters greatly facilitate our review.  Please
understand that we may have additional comments after reviewing
your
amendment and 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 informed decision.  Since the company and its management are in
possession of all facts related to your disclosure, they are
responsible for the accuracy and adequacy of the disclosures they
have made.

      Prior to our declaration of the effective date of the
pending
post-effective amendment pursuant to Section 8(c) of the
Securities
Act, the company should furnish a letter acknowledging that:

* should the Commission or the staff, acting pursuant to delegated
authority, declare the filing effective, it does not foreclose the
Commission from taking any action with respect to the filing;
* the action of the Commission or the staff, acting pursuant to
delegated authority, in declaring the filing effective, does not
relieve the company from its full responsibility for the adequacy
and
accuracy of the disclosure in the filing; and
* the company may not assert the staff comments and the
declaration
of effectiveness as a defense in any proceeding initiated by the
Commission or any person under the federal securities laws of the
United States.

      In addition, please be advised that the Division of
Enforcement
has access to all information you provide to the staff of the
Division of Corporation Finance in connection with our review of
your
filing or in response to our comments on your filing.

      You may contact Daniel Lee at (202) 551-3477 with any
questions.  If you need further assistance, you may contact me at
(202) 551-3462 or Barbara C. Jacobs, Assistant Director, at (202)
551-3730.

	Sincerely,


	Mark P. Shuman
	Branch Chief - Legal

cc:	Via Facsimile
	Jeffrey Small, Esq.
	Albert Cua, Esq.
	Davis Polk & Wardell
	450 Lexington Avenue
	New York, New York 10017
	Telephone: (212) 450-4000
	Facsimile:  (212) 450-3800