Exhibit 99CERT.302

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002:

I, Patrick J. Sheppard, certify that:

1. I have reviewed this report on Form N-CSR of Mellon Institutional Funds
Investment Trust (the "Registrant");

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, changes in net assets, and cash
flows (if the financial statements are required to include a statement of cash
flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in
Rule 30a-3(c) under the Investment Company Act of 1940) and internal control
over financial reporting (as defined in Rule 30a-3(d) under the Investment
Company Act of 1940) 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)  Designed such internal control over financial reporting, or caused
          such internal control over financial reporting to be designed under
          our supervision, to provide reasonable assurance regarding the
          reliability of financial reporting and the preparation of financial
          statements for external purposes in accordance with generally accepted
          accounting principles;

     (c)  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 a date
          within 90 days prior to the filing date of this report based on such
          evaluation; and

     (d)  Disclosed in this report any change in the registrant's internal
          control over financial reporting that occurred during the second
          fiscal quarter of the period covered by this 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(s) and I have disclosed 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:  September 7, 2006                   /s/ PATRICK J. SHEPPARD
                                           -----------------------
                                           Patrick J. Sheppard
                                           President and Chief Executive Officer



Exhibit 99CERT.302

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002:

I, Steven M. Anderson, certify that:

1. I have reviewed this report on Form N-CSR of Mellon Institutional Funds
Investment Trust (the "Registrant");

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, changes in net assets, and cash
flows (if the financial statements are required to include a statement of cash
flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer(s) and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined in
Rule 30a-3(c) under the Investment Company Act of 1940) and internal control
over financial reporting (as defined in Rule 30a-3(d) under the Investment
Company Act of 1940) 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)  Designed such internal control over financial reporting, or caused
          such internal control over financial reporting to be designed under
          our supervision, to provide reasonable assurance regarding the
          reliability of financial reporting and the preparation of financial
          statements for external purposes in accordance with generally accepted
          accounting principles;

     (c)  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 a date
          within 90 days prior to the filing date of this report based on such
          evaluation; and

     (d)  Disclosed in this report any change in the registrant's internal
          control over financial reporting that occurred during the second
          fiscal quarter of the period covered by this 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(s) and I have disclosed 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:  September 7, 2006                            /s/ STEVEN M. ANDERSON
                                                    ----------------------
                                                    Steven M. Anderson
                                                    Vice President and Treasurer