exv31

CERTIFICATIONS

Exhibit 31

I, Judith Segall, certify that:

1. I have reviewed this quarterly report on Form 10-Q of BioTime, Inc.;

2. Based on my knowledge, this quarterly 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 quarterly 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 issuer as of, and for, the periods presented in this report;

4. The issuer’s other certifying officers and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rule 13a-14(c)) for the issuer and have:

(a) Designed such disclosure controls and procedures to ensure that material information relating to the issuer, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which the periodic reports are being prepared;

(b) Evaluated the effectiveness of the issuer’s disclosure controls and procedures as of a date within 90 days prior to the filing date of this quarterly 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 issuer’s other certifying officers and I have disclosed, based on our most recent evaluation, to the issuer’s auditors and the audit committee of issuer’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 issuer’s ability to record, process, summarize and report financial data and have identified for the issuer’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 issuer’s internal controls; and

6. The issuer’s other certifying officers and I have indicated in this quarterly 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: November 15, 2004


		/s/ Judith Segall

		Judith Segall
		Vice-President – Operations
		Member, Office of the President*

* The Office of the President is comprised of the three executive officers of the issuer who collectively exercise the powers of the Chief Executive Officer

CERTIFICATIONS

I, Hal Sternberg, certify that:

1. I have reviewed this quarterly report on Form 10-Q of BioTime, Inc.;

(b) Evaluated the effectiveness of the issuer’s disclosure controls and procedures as of a date within 90 days prior to the filing date of this quarterly 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;

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the issuer’s internal controls; and

Date: November 15, 2004


		/s/ Hal Sternberg

		Hal Sternberg
		Vice-President – Research
		Member, Office of the President*

* The Office of the President is comprised of the three executive officers of the issuer who collectively exercise the powers of the Chief Executive Officer

CERTIFICATIONS

I, Harold Waitz, certify that:

1. I have reviewed this quarterly report on Form 10-Q of BioTime, Inc.;

(b) Evaluated the effectiveness of the issuer’s disclosure controls and procedures as of a date within 90 days prior to the filing date of this quarterly 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;

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the issuer’s internal controls; and

Date: November 15, 2004


		/s/ Harold Waitz

		Harold Waitz
		Vice-President – Regulatory Affairs
		Member, Office of the President*

* The Office of the President is comprised of the three executive officers of the issuer who collectively exercise the powers of the Chief Executive Officer

CERTIFICATIONS

I, Steven A. Seinberg, certify that:

1. I have reviewed this quarterly report on Form 10-Q of BioTime, Inc.;

(b) Evaluated the effectiveness of the issuer’s disclosure controls and procedures as of a date within 90 days prior to the filing date of this quarterly 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;

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the issuer’s internal controls; and

Date: November 15, 2004


		/s/ Steven A. Seinberg

		Steven A. Seinberg
		Chief Financial Officer