Althea T.L. Simmons, 66, the chief of the NAACP's Washington bureau since 1979 and the organization's chief Washington lobbyist, died of respiratory failure Sept. 13 at Howard University Hospital. She had undergone a hip operation.

Miss Simmons joined the NAACP in the mid-1950s. Before moving here, she was associate director of branch and field services in the organization's headquarters in New York. Her duties there included supervising branches and field staff around the nation, membership activites and the youth and college division.

In Washington, Miss Simmons played a role in shaping policies and legislation in civil rights. She remained active in connection with the civil rights bill recently passed by Congress, although she had been hospitalized for four months.

Much of her most valuable work, however, was keeping track of policymakers in a quiet way. She described this in a speech at an NAACP regional banquet in Northern Virginia in 1979.

"It's not enough to just listen to the politicians at election time," she said. "Start monitoring how they vote. Often they will say something on the floor of the House or Senate just to get into the Congressional Record, but they vote just the opposite."

In 1989, she said it was necessary to keep up pressure on matters of concern to blacks and other minorities "because if you don't, people will think the problem is solved."

And when L. Douglas Wilder was elected in Virginia last year, becoming the first black elected governor, Miss Simmons said, "Black {candidates} have to appeal to both blacks and whites . . . . You have to tread a very tight line . . . . I don't think this means any great healing of tensions between races, but it's a breakthrough."

A resident of Washington, Miss Simmons was born in Shreveport, La. She graduated from Southern University and received a law degree from Howard University. She also studied marketing at the University of Illinois.

Her many honors included the President's Award of Washburn University, the Howard University Alumni Award for Postgraduate Achievement in Law and Public Service, the Gertrude E. Rush Award of the National Bar Association, the Patricia Roberts Harris Award of Delta Sigma Theta Sorority and the National Trends and Services Award of Links, Inc.

Miss Simmons was a member of Asbury United Methodist Church in Washington, and she served on various committees of the United Methodist Church Board of Pensions. She was a member of the Delta Sigma Theta Sorority.

Survivors include a sister, Earldean V.S. Robbins of San Francisco.