Exhibit 31.01
CERTIFICATIONS PURSUANT TO
SECTION 302
OF THE SARBANES-OXLEY ACT OF 2002
I, Peter E. Kalan, certify that:
| 1. | I have reviewed this amended report on Form 10-Q/A of CSG Systems International, Inc.; and |
| 2. | Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report. |
| Date: November 24, 2010 | /s/ Peter E. Kalan | |||
| Peter E. Kalan | ||||
| Chief Executive Officer and President |