EX-99.CERT
CERTIFICATION PURSUANT TO RULE 30a-2(a) UNDER THE 1940 ACT AND SECTION 302 OF
THE SARBANES-OXLEY ACT OF 2002

I, Donald C. Burke, Chief Executive Officer (principal executive officer) of BlackRock Municipal Bond Fund, Inc., certify
that:

1. I have reviewed this report on Form N-Q of BlackRock Municipal Bond Fund, Inc.;

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 schedules of investments included in this report fairly present in all material respects
the investments of the registrant as of the end of the fiscal quarter for which the report is filed;

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 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(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: May 20, 2009

/s/ Donald C. Burke
Donald C. Burke
Chief Executive Officer (principal executive officer) of
BlackRock Municipal Bond Fund, Inc.

EX-99.CERT
CERTIFICATION PURSUANT TO RULE 30a-2(a) UNDER THE 1940 ACT AND
SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Neal J. Andrews, Chief Financial Officer (principal financial officer) of BlackRock Municipal Bond
Fund, Inc., certify that:

1. I have reviewed this report on Form N-Q of BlackRock Municipal Bond Fund, Inc.;

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 schedules of investments included in this report fairly present in all
material respects the investments of the registrant as of the end of the fiscal quarter for which the report is
filed;

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 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(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: May 20, 2009

/s/ Neal J. Andrews
Neal J. Andrews
Chief Financial Officer (principal financial officer) of
BlackRock Municipal Bond Fund, Inc.