REPORT OF INDEPENDENT REGISTERED PUBLIC
ACCOUNTING FIRM

To the Shareholders of BlackRock Advantage Large Cap Core
Portfolio, BlackRock Sustainable Balanced Portfolio (formerly,
BlackRock Balanced Capital Portfolio), BlackRock Capital
Appreciation Portfolio, BlackRock Global Allocation Portfolio,
BlackRock Government Money Market Portfolio, BlackRock
High Yield Portfolio, and BlackRock U.S. Government Bond
Portfolio and the Board of Directors of BlackRock Series Fund,
Inc. and BlackRock Series Fund II, Inc.:

In planning and performing our audits of the financial statements of
BlackRock Advantage Large Cap Core Portfolio, BlackRock
Sustainable Balanced Portfolio (formerly, BlackRock Balanced
Capital Portfolio) BlackRock Capital Appreciation Portfolio,
BlackRock Global Allocation Portfolio, and BlackRock Government
Money Market Portfolio of BlackRock Series Fund, Inc., and of
BlackRock High Yield Portfolio and BlackRock U.S. Government
Bond Portfolio of BlackRock Series Fund II, Inc. (the "Funds"), as of
and for the year ended December 31, 2022, in accordance with the
standards of the Public Company Accounting Oversight Board
(United States) (PCAOB), we considered the Funds' internal control
over financial reporting, including controls over safeguarding
securities, as a basis for designing our auditing procedures for the
purpose of expressing our opinion on the financial statements and to
comply with the requirements of Form N-CEN, but not for the
purpose of expressing an opinion on the effectiveness of the Funds'
internal control over financial reporting. Accordingly, we express no
such opinion.

The management of the Funds is responsible for establishing and
maintaining effective internal control over financial reporting. In
fulfilling this responsibility, estimates and judgments by management
are required to assess the expected benefits and related costs of
controls. A company's internal control over financial reporting is a
process designed 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. A company's internal control over
financial reporting includes those policies and procedures that (1)
pertain to the maintenance of records that, in reasonable detail,
accurately and fairly reflect the transactions and dispositions of the
assets of the company; (2) provide reasonable assurance that
transactions are recorded as necessary to permit preparation of
financial statements in accordance with generally accepted
accounting principles, and that receipts and expenditures of the
company are being made only in accordance with authorizations of
management and directors of the company; and (3) provide
reasonable assurance regarding prevention or timely detection of
unauthorized acquisition, use, or disposition of a company's assets
that could have a material effect on the financial statements.
Because of its inherent limitations, internal control over financial
reporting may not prevent or detect misstatements. Also, projections
of any evaluation of effectiveness to future periods are subject to the
risk that controls may become inadequate because of changes in
conditions or that the degree of compliance with the policies or
procedures may deteriorate.
A deficiency in internal control over financial reporting exists when
the design or operation of a control does not allow management or
employees, in the normal course of performing their assigned
functions, to prevent or detect misstatements on a timely basis. A
material weakness is a deficiency, or a combination of deficiencies,
in internal control over financial reporting, such that there is a
reasonable possibility that a material misstatement of the company's
annual or interim financial statements will not be prevented or
detected on a timely basis.
Our consideration of the Funds' internal control over financial
reporting was for the limited purpose described in the first paragraph
and would not necessarily disclose all deficiencies in internal control
that might be material weaknesses under standards established by the
PCAOB. However, we noted no deficiencies in the Funds' internal
control over financial reporting and its operation, including controls
over safeguarding securities, that we consider to be a material
weakness, as defined above, as of December 31, 2022.
This report is intended solely for the information and use of
management and the Board of Directors of the Funds and the
Securities and Exchange Commission and is not intended to be and
should not be used by anyone other than these specified parties.
Deloitte & Touche LLP
Boston, Massachusetts
February 14, 2023