Exhibit 31-8

    CERTIFICATION PURSUANT TO RULE 13a-14(a) AND 15d-14(a) OF THE SECURITIES
                            AND EXCHANGE ACT OF 1934

 I, J. Barry Mitchell, certify that:

1.   I have reviewed this quarterly  report on Form 10-Q/A of Exelon  Generation
     Company, LLC;

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 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 registrant's most recent
     fiscal quarter 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 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.

     Date:   December 15, 2003              /s/ J. Barry Mitchell
                                            ----------------------------
                                            Chief Financial Officer
                                            (Principal Financial Officer)