(Sec. 3) Requires each business center established under the Act to provide to the SBA, as part of an annual SBA programmatic and financial examination of such center: (1) an itemized cost breakdown of actual expenditures; and (2) documentation regarding the amount of matching assistance from non-Federal sources obtained and expended by such center in order to meet matching-funds requirements. Directs the Administrator, after analyzing such information, to determine the programmatic and financial viability of each center. Authorizes the SBA to withhold grant extensions or renewals if the centers do not provide required information, if such information is inadequate, or if examination results are poor. Directs the SBA to report to the small business committees on the effectiveness of all women's business center projects conducted.

(Sec. 4) Establishes a four-year pilot program under which the SBA may award grants on a competitive basis for an additional five-year project to any private nonprofit organization that has received financial assistance under the Act and: (1) is in the final year of a five-year project; or (2) has completed a project financed under the Act and continues to provide assistance to women entrepreneurs. Outlines grant application requirements, including: (1) agreeing to a site visit and an annual programmatic and financial examination; (2) providing information demonstrating appropriate experience in providing assistance to women business owners or potential owners; and (3) providing a five-year plan to serve women business owners and to provide training and services to women who are both socially and economically disadvantaged. Requires participating organizations to: (1) collect and maintain information concerning the assistance provided; and (2) agree to obtain matching cash and in-kind contributions from non-Federal sources for each year of additional program participation.

Authorizes appropriations for FY 2000 through 2003 for the women's business center program, earmarking specified amounts for: (1) selection panel costs, certain post-award costs, and costs related to program monitoring and oversight; and (2) funding sustainability grants under the program (including provisions for the use of unobligated grant funds).

(Sec. 5) Expresses the sense of the Senate that the U.S. Comptroller General should: (1) audit the Federal procurement system regarding Federal contracting involving women-owned small businesses for the preceding three fiscal years; (2) solicit suggestions for increasing the number of Federal contracts awarded to women-owned small businesses; and (3) report to Congress on audit results.

(Sec. 3) Requires each business center established under the Act to provide to the SBA, as part of an annual SBA programmatic and financial examination of such center: (1) an itemized cost breakdown of actual expenditures; and (2) documentation regarding the amount of matching assistance from non-Federal sources obtained and expended by such center in order to meet matching-funds requirements. Directs the Administrator, after analyzing such information, to determine the programmatic and financial viability of each center. Authorizes the SBA to withhold grant extensions or renewals if the centers do not provide required information, if such information is inadequate, or if examination results are poor. Directs the SBA to report to the small business committees on the effectiveness of all women's business center projects conducted.

(Sec. 4) Establishes a four-year pilot program under which the SBA may award grants on a competitive basis for an additional five-year project to any private nonprofit organization that has received financial assistance under the Act and: (1) is in the final year of a five-year project; or (2) has completed a project financed under the Act and continues to provide assistance to women entrepreneurs. Outlines grant application requirements, including: (1) agreeing to a site visit and an annual programmatic and financial examination; (2) providing information demonstrating appropriate experience in providing assistance to women business owners or potential owners; and (3) providing a five-year plan to serve women business owners and to provide training and services to women who are both socially and economically disadvantaged. Requires participating organizations to: (1) collect and maintain information concerning the assistance provided; and (2) agree to obtain matching cash and in-kind contributions from non-Federal sources for each year of additional program participation.

Authorizes appropriations for FY 2000 through 2003 for the women's business center program, earmarking specified amounts for: (1) selection panel costs, certain post-award costs, and costs related to program monitoring and oversight; and (2) funding sustainability grants under the program (including provisions for the use of unobligated grant funds).

(Sec. 5) Expresses the sense of the Senate that the U.S. Comptroller General should: (1) audit the Federal procurement system regarding Federal contracting involving women-owned small businesses for the preceding three fiscal years; (2) solicit suggestions for increasing the number of Federal contracts awarded to women-owned small businesses; and (3) report to Congress on audit results.

Women's Business Centers Sustainability Act of 1999 - Amends the Small Business Act, with respect to the women's business center program, to allow a private organization that has received financial assistance under the program and that is either in the final year of a five-year project or has completed the project to apply for assistance for an additional five-year period. Requires such organizations to agree to obtain matching cash contributions from non-Federal sources.

Extends through FY 2001 the authorization for the program, allowing no more than 40 percent of such amounts to be used for providing such additional assistance.