CERTIFICATION

I, Gifford R. Zimmerman, certify that:

      1. I have reviewed this report on Form N-CSR of Nuveen Floating Rate
Income Opportunity Fund;

      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 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 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: October 5, 2007                      /s/ Gifford R. Zimmerman
                                           -----------------------------
                                           Gifford R. Zimmerman
                                           Chief Administrative Officer
                                           (principal executive officer)


                                   CERTIFICATION

I, Stephen D. Foy, certify that:

      1. I have reviewed this report on Form N-CSR of Nuveen Floating Rate
Income Opportunity Fund;

      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 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 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: October 5, 2007                      /s/ Stephen D. Foy
                                           ------------------------
                                           Stephen D. Foy
                                           Vice President and Controller
                                           (principal financial officer)