<DOCUMENT>
<TYPE>EX-99.77Q3
<SEQUENCE>3
<FILENAME>c28087_ex99-77q3.txt
<TEXT>
CERTIFICATIONS

         I, Robert S. Kapito, certify that:

         1.    I have reviewed this report on Form N-SAR of BlackRock Insured
               Municipal Income Trust;

         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 information included in this
               report, and the financial statements on which the financial
               information is based, 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 officers and I are responsible
               for establishing and maintaining disclosure controls and
               procedures (as defined in rule 30a-2(c) under the Investment
               Company Act) for the registrant and have;

               a.  designed such disclosure controls and procedures 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 as of a date within 90 days prior to
                   the filing date of this report (the "Evaluation Date"); and

               c.  presented in this report our conclusions about the
                   effectiveness of the disclosure controls and procedures based
                   on our evaluation as of the Evaluation Date;

         5.    The registrant's other certifying officers and I have disclosed,
               based

                                       1
<PAGE>

               on our most recent evaluation, 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 in the design or operation of
                   internal controls which could adversely affect the
                   registrant's ability to record, process, summarize, and
                   report financial data and have identified for the
                   registrant's auditors any material weaknesses in internal
                   controls; and

               b.  any fraud, whether or not material, that involves management
                   or other employees who have a significant role in the
                   registrant's internal controls; and

         6.    The registrant's other certifying officers and I have indicated
               in this report whether or not there were significant changes in
               internal controls or in other factors that could significantly
               affect internal controls subsequent to the date of our most
               recent evaluation, including any corrective actions with regard
               to significant deficiencies and material weaknesses.

Date:   April 28, 2003
      ------------------

                                             /s/ Robert S. Kapito
                                             --------------------
                                             Robert S. Kapito
                                             Trustee, President, Chief Executive
                                             Officer



                                       2
<PAGE>

CERTIFICATIONS

         I, Henry Gabbay, certify that:

         1.    I have reviewed this report on Form N-SAR of BlackRock Insured
               Municipal Income Trust;

         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 information included in this
               report, and the financial statements on which the financial
               information is based, 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 officers and I are responsible
               for establishing and maintaining disclosure controls and
               procedures (as defined in rule 30a-2(c) under the Investment
               Company Act) for the registrant and have;

               a.  designed such disclosure controls and procedures 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 as of a date within 90 days prior to
                   the filing date of this report (the "Evaluation Date"); and

               c.  presented in this report our conclusions about the
                   effectiveness of the disclosure controls and procedures based
                   on our evaluation as of the Evaluation Date;

         5.    The registrant's other certifying officers and I have disclosed,
               based

                                       1

<PAGE>

               on our most recent evaluation, 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 in the design or operation of
                   internal controls which could adversely affect the
                   registrant's ability to record, process, summarize, and
                   report financial data and have identified for the
                   registrant's auditors any material weaknesses in internal
                   controls; and

               b.  any fraud, whether or not material, that involves management
                   or other employees who have a significant role in the
                   registrant's internal controls; and

         6.    The registrant's other certifying officers and I have indicated
               in this report whether or not there were significant changes in
               internal controls or in other factors that could significantly
               affect internal controls subsequent to the date of our most
               recent evaluation, including any corrective actions with regard
               to significant deficiencies and material weaknesses.

Date:  April 28, 2003
     -----------------

                                            /s/ Henry Gabbay
                                            -----------------
                                            Henry Gabbay
                                            Treasurer and Principal Financial
                                            Officer



                                       2

</TEXT>
</DOCUMENT>
