**Exhibit 31.1**

I, Kevin J.Sheehan, Chairman and Chief Executive Officer, certify that:

1.                 I have reviewedthis report  on Form 10-K/A (AmendmentNo. 1) filed on April 30, 2007 of Investors Financial Services Corp.amending our Report on Form 10-K filed on February 27, 2007;

2.                 Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

3.                 Based on myknowledge, the financial statements, and other financial information includedin our report on Form 10-K, as amended by this report, fairlypresent in all material respects the financial condition, results of operationsand cash flows of the registrant as of, and for, the periods presented in this report;

4.                 The registrant’sother certifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) for theregistrant and have:

(a)           Designed suchdisclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

(b)          Designed such internalcontrol over financial reporting, or caused such internal control overfinancial reporting to be designed under our supervision, to provide reasonableassurance regarding the reliability of financial reporting and the preparationof financial statements for external purposes in accordance with generallyaccepted accounting principles;

(c)           Evaluated theeffectiveness of the registrant’s disclosure controls and procedures andpresented in our report on Form 10-K our conclusions about theeffectiveness of the disclosure controls and procedures, as of the end of theperiod covered by our report based on such evaluation; and

(d)          Disclosed in our reporton Form 10-K any change in the registrant’s internal control overfinancial reporting that occurred during the registrant’s most recent fiscalquarter (the registrant’s fourth fiscal quarter in the case of an annualreport) that has materially affected, or is reasonably likely to materiallyaffect, the registrant’s internal control over financial reporting; and

5.                 The registrant’sother certifying officer and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the registrant’sauditors and the audit committee of the registrant’s board of directors (orpersons performing the equivalent functions):

(a)           All significantdeficiencies and material weaknesses in the design or operation of internalcontrols over financial reporting which are reasonably likely to adverselyaffect the registrant’s ability to record, process, summarize and reportfinancial information; and

(b)          Anyfraud, whether or not material, that involves management or other employees whohave a significant role in the registrant’s internal control over financialreporting.
| Date: April 30, 2007 |                                    |
|---------------------------|-----------------------------------------|
|                      | /s/ KEVIN J. SHEEHAN                    |   |
|                      | Kevin J. Sheehan                        |
|                      | *Chairman  and Chief Executive Officer* |

 

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