To the disappointment of Arlington officials, the Peace Corps apparently will not be moving its headquarters to Clarendon after all.

The House of Representatives approved an amendment yesterday to the 1987 supplemental appropriations bill that would require the agency to remain in the District of Columbia.

The Senate is expected to follow suit today.

The proposed relocation to the Clarendon Square building at 3033 Wilson Blvd. had been the subject of a bureaucratic battle between the General Services Administration, which favored the move to the less expensive quarters, and the Peace Corps, which cited the medical needs of its volunteers -- and the accessibility of such care downtown -- as one of the chief reasons not to move.

On the sidelines were Arlington officials, who thought the presence of a large government agency such as the Peace Corps would have given Clarendon an identity akin to what it would have if a major corporation were to move its headquarters there.

Although located on the Orange line, Clarendon has not experienced the Metro-inspired redevelopment that areas such as Rosslyn and Ballston have enjoyed.

"I'm disappointed," Albert C. Eisenberg, chairman of the Arlington County Board, said yesterday. "A first-class tenant like {the Peace Corps} was one of the elements that would have made Clarendon jell."

The move would have consolidated three Peace Corps offices now downtown, including agency headquarters, and would have involved 540 employes.

GSA regional administrator Richard M. Hadsell said the agency is trying to find another federal tenant for the Clarendon Square building, where it now has a 10-year lease on office space. "Maybe I'll ask ACTION if they want to go out there," Hadsell said.

Another possible tenant is the Defense Department. The Defense Intelligence Agency recently leased offices in a nearby building, he said.

During the 1950s, Clarendon was the commercial hub of Northern Virginia. The development of regional shopping malls hastened the area's decline.

In the past year, several large office buildings have been built in Clarendon, which now has a thriving commercial strip of mostly Asian shops and restaurants along Wilson Boulevard.

But the area needs major physical improvements, Eisenberg said. On Saturday the county board approved a $62,500 grant to the Clarendon Alliance, a public and private partnership that is to oversee the area's revival and market it as an "urban village" that is "a good place to both live and work," Eisenberg said.

Clarendon's image had nothing to do with the Peace Corps' opposition to relocating in the area, agency spokeswoman Alix R. Glen said yesterday.

"Our location is a functional matter," she said. Volunteers who become ill abroad are brought back and treated at George Washington University Hospital. "It's of vital importance to be as close as possible and as accessible as possible to proper medical facilities and the State Department," with which the agency has continual dealings, she said.

"We are grateful Congress has recognized the importance of the Peace Corps' maintaining a downtown location," she added.