"I am announcing today my intention to complete my service in the House of Representatives at the end of the current session but not to be a candidate for re-election to the 113th Congress," Dicks said Friday in a prepared statement.
Dicks, the top Democrat on the powerful House Appropriations Committee, is currently serving his 18th term in Congress for Washington state's 6th Congressional District, which includes downtown Tacoma, much of Kitsap County and the Olympic Peninsula.
He was first elected to office in 1976 after serving for eight years on the staff of legendary U.S. Sen. Warren G. Magnuson, D-Wash. He is currently the longest-serving member of the state's congressional delegation.
The 71-year-old lawmaker, who grew up in Bremerton and graduated from the University of Washington, has earned a reputation as a staunch advocate of the Pentagon and is a defender of the Boeing Co. and its unionized workforce. The company employs thousands of people in his district.
Dicks said he and his wife Suzie "have made the decision to change gears and enjoy life at a different pace."
"It was time to do something else, to work with my family, my grandchildren, and Suzie and I decided we had had a really good run, and let's leave it at this point, he said in an interview with KOMO Newsradio.
"I just want to say 'thank you' to the people of this state and to my district for supporting me over these many years, and I just felt it was time."
Dicks currently is serving as the most senior Democrat on the House Appropriations Committee, as well as the appropriations panels for interior and defense. Over the years, he has helped steer billions of dollars toward Washington state military bases and programs. He also was known informally as the "Congressman from Boeing."
U.S. Sen. Patty Murray, reacting to the news of Dicks' retirement, said he is a "true Washington state institution" and "our state's quarterback here in Congress."
"I can't imagine our delegation without him," Murray said. "Norm will retire from Congress leaving behind an incredible legacy of public service. Washington state families will benefit from his hard work, passionate advocacy and tremendous contributions for decades to come."
Dicks said he has seen many changes in the years since he first started working for Sen. Magnuson in 1968.
"Those were better times," he said. "Democrats and Republicans worked together."
In the years since, Dicks really had only one close race for re-election - in 1980, the year of the Reagan landslide, when he was challenged by his former law school professor Jim Beaver.
In most other races, Dicks easily coasted to re-election with 60 percent to 65 percent of the vote.
Dicks' retirement could provide an opening for Republicans, who might now have a chance in a district they haven't seriously contested for in years.
"I think it's a seat that the Democrats ought to retain. I think we're going to have to put forward a strong and credible replacement. Whoever that is, is going to have big shoes to fill," said Sandeep Kaushik, a Seattle Democratic political consultant.
Dicks said his proudest achievements while in office include protecting the waters of Puget Sound, restoring vitality to downtown Tacoma and Bremerton, maintaining a strong national defense, restoring the Elwha River salmon runs and supporting Boeing programs that employ tens of thousands of Washington state workers.
He said his biggest regret during his years in office was voting for the Iraq War.
"I'm still glad Saddam Hussein is not there, but I feel we were misled - not intentionally misled - but we were not given accurate information, and if we had known Saddam Hussein did not have weapons of mass destruction, I don't think Congress would even have been asked to vote on that."
Asked who he felt was the best president during his time in Congress, Dicks did not hesitate before naming Bill Clinton.
"Bill Clinton (was best) because he was able to get the economy restored. We had three or four balanced budgets. Had it not been for al Qaida and the attacks in New York, Pennsylvania and D.C., we would have had the deficit completely paid off by now."