Exhibit 31.2

CERTIFICATION OF CHIEF FINANCIAL OFFICER 
                  PURSUANT TO 
                 SECTION 13(a) OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
                  AS ADOPTED PURSUANT TO 
                  SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Maureen L. Lamb certify that:

1.    I have reviewed this annual report on Form 10-K of
Kyphon 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 the 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 regaring the realiability 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 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:February 28, 2007

By: /s/ Maureen L. Lamb
               Maureen L. Lamb
                 Vice President, Chief Operating Officer
               (Principal Accounting and Financial Officer)

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