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                                                                  EXHIBIT 31.1
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                                CERTIFICATION


         I, Zsolt Rumy, certify that:

         1. I have reviewed this annual report on Form 10-K of Zoltek
Companies, 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(s) 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
quarterly 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 (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(s) 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
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:  January 3, 2006

                                            By: /s/ Zsolt Rumy
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                                                    Zsolt Rumy
                                                    Chief Executive Officer