10-K


Exhibit
31.2


CERTIFICATION




I,
Robert P. Ambrosini, certify that:




1. I have reviewed
this annual report on Form 10-K of The Bureau of National Affairs,
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 financial statements, and other financial information included in
this report, fairly present in all material respects the financial condition,
results of operations and 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 Exchange Act Rules 13a-15(e)
and 15d-15(e)) and internal control over financial reporting (as defined in
Exchange Act Rules 13a-15f and 15d-15(f)) 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 the end of the period covered by 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 and I have disclosed, based on our most recent
evaluation of internal control over financial reporting, to the registrant's
auditors and the audit committee of registrant's board of
directors:




(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.




03/24/2010
              /s/Robert
      P. AmbrosiniDate
              Robert  P.
      AmbrosiniExecutive Vice President
      and Chief Financial Officer








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