DALLAS, TEXAS, February 7, 2000 - With the launch of Allegiance Telecom, Inc. (Nasdaq: ALGX) services in Denver, local businesses in the Mile High City now have an expanded choice in telecommunications service providers. Allegiance is targeting small and medium-sized businesses in the Denver area to provide them with economical local, long distance, international calling, high-speed data transmission and Internet services.

Allegiance is a well-established facilities-based competitive local exchange carrier (CLEC), offering businesses a complete package of telecommunications services. The company is targeting 36 major metropolitan areas in the United States with its "one-stop shopping" approach. In addition to Denver, Allegiance Telecom is currently operational in 19 other markets, including Atlanta, Baltimore, Boston, Chicago, Dallas, Detroit, Fort Worth, Houston, Long Island, Los Angeles, New York, Northern New Jersey, Oakland, Orange County, Philadelphia, San Diego, San Francisco, San Jose and Washington D.C.

"Denver businesses are open to alternative choices for telecommunications services," said Tony Parella, Allegiance Telecom senior vice president of sales and customer care. "Businesses want reliable, economical alternatives to their current service providers. Allegiance Telecom provides a single source for all the telecommunications requirements of businesses including local, long distance, high-speed data transmission and Internet services. We offer our customers the value of state-of-the-art technology, consolidated billing arrangements and superior customer service," he said.

Allegiance Telecom's local sales office is located at 7979 Tufts Avenue Parkway, #1000, in Denver, and can be reached at 303/713-7100.

Allegiance is a facilities-based CLEC headquartered in Dallas, Texas. The Company's web address is www.allegiancetele.com. Allegiance's common stock is traded on the Nasdaq National Market under the symbol ALGX.