Exhibit 31

                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER
                         SECURITY CAPITAL ASSURANCE LTD
            PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002
                     (Chapter 98, Title 15 U.S.C. SS. 7241)

I, Paul S. Giordano, certify that:

1.   I have reviewed this Quarterly Report on Form 10-Q of Security Capital
     Assurance Ltd;

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;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this report, fairly present in all material
     respects the financial condition, results of operations and cash flows of
     the registrant as of, and for, the periods presented in this report;

4.   The registrant's other certifying officer and I are responsible for
     establishing and maintaining disclosure controls and procedures (as defined
     in Exchange Act Rules 13a- 15(e) and 15d-15(e)) for the registrant and
     have:

     a)   Designed such disclosure controls and procedures, or caused such
          disclosure controls and procedures to be designed under our a
          supervision, to ensure that material information relating to the
          registrant, including its consolidated subsidiaries, is made known to
          us by others within those entities, particularly during the period in
          which this report is being prepared;

     b)   Evaluated the effectiveness of the registrant's disclosure controls
          and procedures and presented in this report our conclusions about
          the effectiveness of the disclosure controls and procedures, as of the
          end of the period covered by this report based on such evaluation; and

     c)   Disclosed in this report any change in the registrant's internal
          control over financial reporting that occurred during the d
          registrant's most recent fiscal quarter (the registrant's fourth
          fiscal quarter in the case of an annual report) that has materially
          affected, or is reasonably likely to materially affect, the
          registrant's internal control over financial reporting; and

5.   The registrant's other certifying officer and I have disclosed, based on
     our most recent evaluation of internal control over financial reporting, to
     the registrant's auditors and the audit committee of the registrant's board
     of directors (or persons performing the equivalent functions):

     a)   All significant deficiencies and material weaknesses in the design or
          operation of internal control over financial reporting which a are
          reasonably likely to adversely affect the registrant's ability to
          record, process, summarize and report financial information; and

     b)   Any fraud, whether or not material, that involves management or other
          employees who have a significant role in the registrant's internal
          control over financial reporting.


Dated: May 14, 2007

                                           /s/ PAUL S. GIORDANO
                                           PAUL S. GIORDANO
                                           President and Chief Executive Officer
                                           Security Capital Assurance Ltd

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                    CERTIFICATION OF CHIEF FINANCIAL OFFICER
                         SECURITY CAPITAL ASSURANCE LTD
            PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002
                     (Chapter 98, Title 15 U.S.C. SS. 7241)

I, David P. Shea, certify that:

1.   I have reviewed this Quarterly Report on Form 10-Q of Security Capital
     Assurance Ltd;

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;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this report, fairly present in all material
     respects the financial condition, results of operations and cash flows of
     the registrant as of, and for, the periods presented in this report;

4.   The registrant's other certifying officer and I are responsible for
     establishing and maintaining disclosure controls and procedures (as defined
     in Exchange Act Rules 13a- 15(e) and 15d-15(e)) for the registrant and
     have:

     a)   Designed such disclosure controls and procedures, or caused such
          disclosure controls and procedures to be designed under our a
          supervision, to ensure that material information relating to the
          registrant, including its consolidated subsidiaries, is made known to
          us by others within those entities, particularly during the period in
          which this report is being prepared;

     b)   Evaluated the effectiveness of the registrant's disclosure controls
          and procedures and presented in this report our conclusions c about
          the effectiveness of the disclosure controls and procedures, as of the
          end of the period covered by this report based on such evaluation; and

     c)   Disclosed in this report any change in the registrant's internal
          control over financial reporting that occurred during the registrant's
          most recent fiscal quarter (the registrant's fourth fiscal quarter in
          the case of an annual report) that has materially affected, or is
          reasonably likely to materially affect, the registrant's internal
          control over financial reporting; and

5.   The registrant's other certifying officer and I have disclosed, based on
     our most recent evaluation of internal control over financial reporting, to
     the registrant's auditors and the audit committee of the registrant's board
     of directors (or persons performing the equivalent functions):

     a)   All significant deficiencies and material weaknesses in the design or
          operation of internal control over financial reporting which a are
          reasonably likely to adversely affect the registrant's ability to
          record, process, summarize and report financial information; and

     b)   Any fraud, whether or not material, that involves management or other
          employees who have a significant role in the registrant's internal
          control over financial reporting.


Dated: May 14, 2007

                                                 /s/ DAVID P. SHEA
                                                 DAVID P. SHEA
                                                 Executive Vice President and
                                                 Chief Financial Officer
                                                 Security Capital Assurance Ltd