1. Name and Address of Reporting Person NAFUS, EDWARD C. 7887 E. Belleview Avenue Suite 1000 Englewood, CO 80111 USA 2. Issuer Name and Ticker or Trading Symbol CSG Systems International, Inc. (CSGS) 3. IRS or Social Security Number of Reporting Person (Voluntary) 4. Statement for Month/Year 2001 5. If Amendment, Date of Original (Month/Day/Year) 6. Relationship of Reporting Person(s) to Issuer (Check all applicable) ( ) Director ( ) 10% Owner ( ) Officer (give title below) (X) Other (specify below) Executive Vice President 7. Individual or Joint/Group Filing (Check Applicable Line) (X) Form filed by One Reporting Person ( ) Form filed by More than One Reporting Person TABLE I -- Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned +---------------------------------+----------+-------------+-----------------------------+----------------+-----------+------------+ |1. Title of Security |2. Trans- |3. Trans- |4. Securities Acquired (A) |5. Amount of |6. Owner- |7. Nature | | | action | action | or Disposed of (D) | Securities | ship | of In- | | | Date | Code | | Beneficially | Form: | direct | | | | | | Owned at | Direct | Bene- | | | (Month/ | | | End of | (D) or | ficial | | | Day/ | +-----------+------+----------+ Year | Indirect| Owner- | | | Year) | |Amount |A/D |Price | | (I) | ship | +---------------------------------+----------+-------------+-----------+------+----------+----------------+-----------+------------+ Common Stock 17080 D TABLE II -- Derivative Securities Acquired, Disposed of, or Beneficially Owned +-------------+--------+----------+---------+-----------+---------------------+----------------+----------+--------+-------+-------+ |1. |2. |3. |4. |5. |6. |7. |8. |9. |10. |11. | | | | | | | | | |Number |Owner- | | | | | | | | | | |of |ship | | | | | | | | | | |Deriv- |Form of| | | | | | | | |Title and Amount| |ative |Deriv- | | | | | | | | |of Underlying | |Secur- |ative |Nature | | |Conver- | | |Number of | |Securities | |ities |Secur- |of | | |sion or | | |Derivative |Date Exercisable +-------+--------+ |Benefi- |ity: |In- | | |Exercise| | |Securities |and Expiration Date | |Amount | |cially |Direct |direct | | |Price of|Transac- |Transac- |Acquired(A)|(Month/Day/Year) | |or | |Owned |(D) or |Bene- | |Title of |Deriv- |tion Date |tion Code|Disposed(D)+----------+----------+ |Number |Price of |at End |In- |ficial | |Derivative |ative |(Month/ | +-----+-----+Date Exer-|Expira- | |of |Derivative|of |direct |Owner- | |Security |Security|Day/Year) | |(A) |(D) |cisable |tion Date |Title |Shares |Security |Year |(I) |ship | +-------------+--------+----------+---------+-----+-----+----------+----------+-------+--------+----------+--------+-------+-------+ Stock Options $21 08/18/2008 Common 160120 D (Right to buy) Stock Stock Options $26.7188 11/17/2008 Common 80000 D (Right to buy) Stock Stock Options $34.43 12/14/2001 A 37500 12/14/2002 12/14/2011 Common 37500 $0.0000 37500 D (Right to buy) StockStock Options $38.4375 01/07/2010 Common 25000 D (Right to buy) Stock Stock Options $47 01/17/2011 Common 35000 D (Right to buy) Stock Explanation of Responses: SIGNATURE OF REPORTING PERSON /s/ EDWARD C. NAFUS DATE 02/01/2002 This stock option is exercisable in 4 equal installments.