SECTION 302 CERTIFICATIONS
I, Michele G. Van Leer, certify that:
1. I have reviewed this report on Form N-CSR of John Hancock Variable Series
Trust I;
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, changes in net assets, and cash
flows (if the financial statements are required to include a statement of 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
Rule 30a-2(c) under the Investment Company Act of 1940) for the registrant and
have:
a) designed such disclosure controls and procedures 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) evaluated the effectiveness of the registrant's disclosure controls
and procedures as of a date within 90 days prior to the filing date of
this report (the "Evaluation Date"); and
c) presented in this report our conclusions about the effectiveness of
the disclosure controls and procedures based on our evaluation as of
the Evaluation Date;
5. The registrant's other certifying officer and I have disclosed, based on our
most recent evaluation, 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 in the design or operation of internal
controls which could adversely affect the registrant's ability to
record, process, summarize, and report financial data and have
identified for the registrant's auditors any material weaknesses in
internal controls; and
b) any fraud, whether or not material, that involves management or
other employees who have a significant role in the registrant's
internal controls; and
6. The registrant's other certifying officer and I have indicated in this report
whether or not there were significant changes in internal controls or in other
factors that could significantly affect internal controls subsequent to the date
of our most recent evaluation, including any corrective actions with regard to
significant deficiencies and material weaknesses.
Date: August 13, 2004 /s/ MICHELE G. VAN LEER
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Michele G. Van Leer
Chairman
SECTION 302 CERTIFICATIONS
I, Raymond F. Skiba, certify that:
1. I have reviewed this report on Form N-CSR of John Hancock Variable Series
Trust I;
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, changes in net assets, and cash
flows (if the financial statements are required to include a statement of 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
Rule 30a-2(c) under the Investment Company Act of 1940) for the registrant and
have:
a) designed such disclosure controls and procedures 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) evaluated the effectiveness of the registrant's disclosure controls
and procedures as of a date within 90 days prior to the filing date of
this report (the "Evaluation Date"); and
c) presented in this report our conclusions about the effectiveness of
the disclosure controls and procedures based on our evaluation as of
the Evaluation Date;
5. The registrant's other certifying officer and I have disclosed, based on our
most recent evaluation, 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 in the design or operation of internal
controls which could adversely affect the registrant's ability to
record, process, summarize, and report financial data and have
identified for the registrant's auditors any material weaknesses in
internal controls; and
b) any fraud, whether or not material, that involves management or
other employees who have a significant role in the registrant's
internal controls; and
6. The registrant's other certifying officer and I have indicated in this report
whether or not there were significant changes in internal controls or in other
factors that could significantly affect internal controls subsequent to the date
of our most recent evaluation, including any corrective actions with regard to
significant deficiencies and material weaknesses.
Date: August 13, 2004 /s/ RAYMOND F. SKIBA
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Raymond F. Skiba
Treasurer