Lewis & Thos. Saltz Co., a haberdasher that clothed congressmen, businessmen and lobbyists for the past 50 years, is closing its doors.

With a large advertisement in Sunday's Washington Post, the retailer confirmed weeks of rumors that the company -- which in its heyday numbered five stores in the metropolitan area -- is going out of business.

After weeks of denying rumors that the company was closing, Saltz officials yesterday said the doors will be shut at the one remaining Saltz store at Connecticut Avenue and K Street NW as soon as all the merchandise is sold. About 20 employes will be out of work.

In the store's place will be a Peoples Drug Store.

Steven Silver, Saltz's vice president, said the closing might come within two weeks, given the large number of shoppers at the store yesterday seeking bargains on the tailored men's clothes. Lines were long as customers waited to pay for goods that some said they couldn't have afforded before the going-out-of-business sale.

In sharp contrast to the days of yore, no alterations were being provided. Nor were store credit cards accepted.

The closing marks the end of an era for the company that was begun in 1936 by two brothers who came to Washington during the Depression from Crisfield, Md., where their father operated a general store.

"It's a business decision," Silver said in explaining why the company's owners decided to sell the store they bought less than three years ago, hoping to revitalize it as a fashionable merchandiser. With the 25-year-old lease about to expire and the new rent "substantially higher. . . we found out we couldn't continue business in this spot."

Silver said, "There is a possibility within the next year" that the Saltz name might be revived by "interested parties wanting to reap the benefits" of the retailer's reputation in Washington.

Since 1936, the company has changed hands many times, with the Saltz brothers selling out in the mid-1950s.

Lewis Saltz died shortly afterward. Thomas Saltz lives in the Washington area. He bought the Georgetown University Shop after he left Lewis & Thos. Saltz Co., but sold the shop several years ago.

Retailing officials say the Saltz company's most recent troubles began when it was sold in the late 1970s to Washington real estate developers Theodore Lerner and Albert Abrahamson. Lerner and Abrahamson tried to upgrade the traditional image of the chain and make it more fashion-oriented. In the process, retailing experts say, the company alienated its traditional clientele.

In late 1983, Lerner and Abrahamson sold the chain to Spencer Hays and Robert Schaich. Schaich was a former executive with a Cincinnati clothier; Hays is a Nashville publisher and an investor in other men's retail and manufacturing ventures.

"The company has shown a 180-degree turnaround within the past year," Silver said. "But because of the real estate end of the business, we found we had to vacate our location."