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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934
                           (Amendment No. __________)*


                         CSG Systems International Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)


                          Common Stock, par value $0.01
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    126349109
--------------------------------------------------------------------------------
                                 (CUSIP Number)


                                 August 6, 2004
--------------------------------------------------------------------------------
            (Date of Event Which Requires Filing of this Statement)


     Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

          [_] Rule 13d-1(b)

          [X] Rule 13d-1(c)

          [_] Rule 13d-1(d)

----------
*    The remainder of this cover page shall be filled out for a reporting
     person's initial filing on this form with respect to the subject class of
     securities, and for any subsequent amendment containing information which
     would alter the disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).





CUSIP No.    126349109
            ---------------------


1.  NAME OF REPORTING PERSONS
    I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

    Ahmet H. Okumus

2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
    INSTRUCTIONS)                                                        (a) [_]
                                                                         (b) [X]

3.  SEC USE ONLY



4.  CITIZENSHIP OR PLACE OF ORGANIZATION

    Republic of Turkey

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.  SOLE VOTING POWER

    0

6.  SHARED VOTING POWER

    2,695,942

7.  SOLE DISPOSITIVE POWER

    0

8.  SHARED DISPOSITIVE POWER

    2,695,942

9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

    2,695,942

10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE
    INSTRUCTIONS)

                                                                             [_]

11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     5.21%

12. TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

     IN

--------------------------------------------------------------------------------





CUSIP No.    126349109
            ---------------------


Item 1(a).  Name of Issuer:


            CSG Systems International Inc.
            --------------------------------------------------------------------

      (b). Address of Issuer's Principal Executive Offices:


           7887 East Belleview Avenue
           Suite 1000
           Englewood, CO 80111

          ----------------------------------------------------------------------


Item 2(a).  Names of Persons Filing:


            Ahmet H. Okumus
            --------------------------------------------------------------------

      (b).  Address of Principal Business Office, or if None, Residence:

            850 Third Avenue, 10th Floor
            New York, New York 10022
            --------------------------------------------------------------------

      (c).  Citizenship:

            Ahmet H. Okumus - Republic of Turkey
            --------------------------------------------------------------------

      (d). Title of Class of Securities:


            Common Stock, par value $0.01 (the "Common Stock")

            --------------------------------------------------------------------

      (e).  CUSIP Number:


            126349109
            --------------------------------------------------------------------


Item 3.     If This Statement is filed pursuant to ss.240.13d-1(b) or
            240.13d-2(b), or (c), check whether the person filing is a:

     (a)   [_] Broker or dealer registered under Section 15 of the Exchange
               Act (15 U.S.C. 78c).

     (b)   [_] Bank as defined in Section 3(a)(6) of the Exchange Act (15
               U.S.C. 78c).

     (c)   [_] Insurance company as defined in Section 3(a)(19) of the
               Exchange Act (15 U.S.C. 78c).

     (d)   [_] Investment company registered under Section 8 of the
               Investment Company Act of 1940 (15 U.S.C. 80a-8).

     (e)   [_] An investment adviser in accordance with
               s.240.13d-1(b)(1)(ii)(E);

     (f)   [_] An employee benefit plan or endowment fund in accordance with
               s.240.13d-1(b)(1)(ii)(F);

     (g)   [_] A parent holding company or control person in accordance with
               Rule 13d-1(b)(1)(ii)(G);

     (h)   [_] A savings association as defined in Section 3(b) of the
               Federal Deposit Insurance Act (12 U.S.C.1813);

     (i)   [_] A church plan that is excluded from the definition of an
               investment company under Section 3(c)(14) of the Investment
               Company Act of 1940 (15 U.S.C. 80a-3);

     (j)   [_] Group, in accordance with s.240.13d-1(b)(1)(ii)(J).

Item 4.  Ownership.

     Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

     (a)  Amount beneficially owned:

          Ahmet H. Okumus - 2,695,942
          ----------------------------------------------------------------------

     (b)  Percent of class:

          Ahmet H. Okumus - 5.21%
        ----------------------------------------------------------------------

     (c)  Number of shares as to which the person has:

          Ahmet H. Okumus

          (i)   Sole power to vote or to direct the vote               0
                                                        -----------------------,


          (ii) Shared power to vote or to direct the vote       2,695,942
                                                          ---------------------,


          (iii) Sole power to dispose or to direct the                 0
                disposition of                            _____________________,


          (iv)  Shared power to dispose or to direct the       2,695,942
                disposition of                            _____________________.


Item 5.  Ownership of Five Percent or Less of a Class.

     If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following [ ].

               Not applicable.
         -----------------------------------------------------------------------


Item 6.  Ownership of More Than Five Percent on Behalf of Another Person.

     If any other person is known to have the right to receive or the power to
direct the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified. A listing of the shareholders of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employee benefit plan, pension fund or endowment fund is not required.

               Ahmet H. Okumus ("Okumus") with respect to the shares of Common
               Stock the Company are also beneficially owned by (a) (i) Okumus
               Opportunity Fund, Ltd., (ii) Okumus Technology Value Fund, Ltd.,
               (iii) Okumus Market Neutral Fund, Ltd., and (iv) Okumus
               Diversified Value Fund, Ltd., all of which are international
               business companies incorporated in the British Virgin Islands,
               for which Okumus Capital, LLC, a Delaware limited liability
               company ("OC") of which Okumus is the managing member, serves as
               the investment manager; (b) Okumus Opportunity Partners, LP, a
               Delaware limited partnership, for which Okumus Advisors, LLC, a
               Delaware limited liability company of which Okumus is the
               managing member, serves as general partner and investment
               advisor; (c) Okumus Technology Value Partners, LP, a Delaware
               limited partnership, for which Okumus Technology Advisors, LLC, a
               Delaware limited liability company of which Okumus is the
               managing member, serves as general partner and investment advisor
               (d) Okumus Market Neutral Partners, LP, a Delaware limited
               partnership, for which Okumus Market Neutral Advisors, LLC, a
               Delaware limited liability company of which Okumus is the
               managing member, serves as general partner and investment
               advisor; and (e) Okumus Diversified Value Partners, L.P., a
               Delaware limited partnership, for which Okumus Diversified
               Advisors, LLC, a Delaware limited liability company of which
               Okumus is the managing member, serves as general partner and
               investment advisor. In addition, OC manages, on a discretionary
               basis, a separate account for an unrelated entity, Daiwa Super
               Hedge Fund Ltd.

               The Reporting Person and all of the foregoing entities
               affirmatively disclaim being a "group" for purposes of Section 16
               of the Securities Exchange Act of 1934, as amended.
         -----------------------------------------------------------------------


Item  7. Identification and Classification of the Subsidiary Which Acquired
         the Security Being Reported on by the Parent Holding Company or Control
         Person.

     If a parent holding company or Control person has filed this schedule,
pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach an
exhibit stating the identity and the Item 3 classification of the relevant
subsidiary. If a parent holding company or control person has filed this
schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating
the identification of the relevant subsidiary.

               Not applicable.
         -----------------------------------------------------------------------


Item 8.  Identification  and  Classification  of Members of the Group.

     If a group has filed this schedule pursuant to ss.240.13d-1(b)(1)(ii)(J),
so indicate under Item 3(j) and attach an exhibit stating the identity and Item
3 classification of each member of the group. If a group has filed this schedule
pursuant to ss.240.13d-1(c) or ss.240.13d-1(d), attach an exhibit stating the
identity of each member of the group.

               Not applicable.
         -----------------------------------------------------------------------


Item 9.  Notice of Dissolution of Group.

     Notice of dissolution of a group may be furnished as an exhibit stating the
date of the dissolution and that all further filings with respect to
transactions in the security reported on will be filed, if required, by members
of the group, in their individual capacity. See Item 5.

               Not applicable.
          ----------------------------------------------------------------------

Item 10.  Certification.


          By signing below I certify that, to the best of my knowledge and
          belief, the securities referred to above were not acquired and are not
          held for the purpose of or with the effect of changing or influencing
          the control of the issuer of the securities and were not acquired and
          are not held in connection with or as a participant in any transaction
          having such purpose or effect.





                                    SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


Date: August 16, 2004
                                            /s/ Ahmet H. Okumus# **
                                            -----------------------------
                                                Ahmet H. Okumus

#  The Reporting Person affirmatively disclaims being a "group" for purposes of
   Section 16 of the Securities Exchange Act of 1934, as amended, with any of Of
   the entities identified in Item 6 above.

** The Reporting Persons disclaim beneficial ownership in the Common Stock,
   except to the extent of their pecuniary interest therein.

The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
this statement, provided, however, that a power of attorney, for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.

Note. Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See s.240.13d-7 for other
parties for whom copies are to be sent.

Attention. Intentional misstatements or omissions of fact constitute federal
criminal violations (see 18 U.S.C. 1001).


21952.0001 #506202