The Twin Bridges Marriott, the first hotel in Marriott Corp.'s 361-hotel empire, will cease to be a Marriott hotel next year, and the property may be redeveloped, the owners of the site near the 14th Street Bridge in Arlington said yesterday.

The property is owned by Equitable Real Estate Management Inc., which bought the hotel from Marriott in 1978. Marriott continues to operate the hotel, which opened in 1957.

Marriott has traditionally developed hotels and then sold the real estate to others while continuing to manage the facilities.

Equitable officials said yesterday that the company has no plans to sell the property, but declined to comment on how it might be used.

Equitable already is one of the largest investors in Washington area real estate, with more than $2 billion in projects such as Metropolitan Square and International Square in the District and King Street Station in Alexandria.

Equitable has worked in partnership with the Oliver Carr Co. on many of its projects.

Roger Conner, a spokesman for Marriott's hotel division, said yesterday that the Bethesda company had agreed to give up the aging, low-rise hotel because it "isn't really representative of our current product today."

"I certainly think that the property does represent an important milestone in being our first hotel," Conner said.

However, he said, "We only grew to where we are by being on top of the marketplace."

Marriott has two other hotels in the Crystal City area near the Twin Bridges Marriott and a total of 11 hotel properties in the Washington area.

The approximately 300 Marriott employees at the hotel have been notified of the agreement with Equitable, Conner said. Many workers there are long-time Marriott employees who may retire. He said others will be assured of similar or better opportunities at other Marriott hotels in the area or other local Marriott businesses, such as restaurants or food-service operations.