<DOCUMENT>
<TYPE>EX-99.77B ACCT LTTR
<SEQUENCE>2
<FILENAME>HQLex77b.txt
<DESCRIPTION>AUDIT LETTER
<TEXT>
REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Trustees and Shareholders of
Tekla Life Sciences Investors

In planning and performing our audit of the financial
statements of Tekla Life Sciences Investors (the "Fund") as
of and for the year ended September 30, 2017, in
accordance with the standards of the Public Company
Accounting Oversight Board (United States) (PCAOB), we
considered the Fund's 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-
SAR, but not for the purpose of expressing an opinion on
the effectiveness of the Fund's internal control over
financial reporting. Accordingly, we express no such opinion.

The management of the Fund 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
fund'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 fund'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 fund; (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 fund are being made only in accordance
with authorizations of management and trustees of
the fund; and (3) provide reasonable assurance regarding
prevention or timely detection of unauthorized
acquisition, use, or disposition of a fund'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
a fund's annual or interim financial statements will not be
prevented or detected on a timely basis.

Our consideration of the Fund's 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 Fund's
internal control over financial reporting and its operation,
including controls for safeguarding securities, that we
consider to be a material weakness, as defined above, as of
September 30, 2017.

This report is intended solely for the information and use
of management, the Trustees of Tekla Life Sciences
Investors 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
November 20, 2017






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