DALLAS, TEXAS, March 19, 1999 - Allegiance Telecom, Inc. (Nasdaq: ALGX), a competitive local exchange carrier (CLEC), today announced the filing of a Registration Statement with the Securities and Exchange Commission relating to a proposed public offering of 10,000,000 shares of common stock.

This press release shall not constitute an offer to sell or a solicitation of an offer to buy the offered shares, nor shall there be any sale of the offered shares in any State in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such State. An offering of the shares shall be made only by means of a prospectus.

Allegiance offers businesses a complete package of telecommunications services, including local, long distance, international calling, high-speed data transmission and Internet services. Allegiance is targeting 24 major metropolitan areas in the U.S. with its "one-stop shopping" approach. The Company's web address is: www.allegiancetele.com.