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		                                               EXHIBIT 31.02

CERTIFICATIONS

I, Kevin Perry, Chief Financial Officer of Demeter Management Corporation
(?Demeter?), the general partner of the registrant, Dean Witter
Diversified Futures Fund III L.P., certify that:

1.	I have reviewed this annual report on Form 10-K of the registrant;

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-15(f) 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
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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 (the registrant?s fourth
fiscal quarter in the case of an annual report) 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 Demeter?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: March 31, 2006    BY: /s/ Kevin Perry
                                Kevin Perry
                                Chief Financial Officer,
                                Demeter Management Corporation,
                                general partner of the registrant