<Page>
EXHIBIT EX-99.CERT
CERTIFICATION PURSUANT TO SECTION 302
OF THE SARBANES-OXLEY ACT
I, Robert M. Zakem, certify that:
1. I have reviewed this report on Form N-CSR of SunAmerica Strategic
Investment Series, 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, 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 officers and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined
in rule 30a-2(c) under the Investment Company Act) 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 officers 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 officers 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: July 3, 2003
/s/Robert M. Zakem
- ------------------
Robert M. Zakem
President
<Page>
I, Donna M. Handel, certify that:
1. I have reviewed this report on Form N-CSR of SunAmerica Strategic
Investment Series, 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, 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 officers and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined
in rule 30a-2(c) under the Investment Company Act) 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 officers 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 officers 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: July 3, 2003
/s/Donna M. Handel
- ------------------
Donna M. Handel
Treasurer