Washington wore the home uniforms of the 1943 Homestead Grays, and St. Louis wore road uniforms from the St. Louis Stars.
Nationals manager Manny Acta said that wearing the Grays uniform was something the team took great pride in.
"We owe these guys, who played before us," Acta said. "It's the least we could do for these guys."
The Homestead Grays began in Pittsburgh but split their home games between Pittsburgh and Washington in the late 1930s and '40s, playing in Washington's Griffith Stadium.
Hall of Famer Josh Gibson played for the team during that time, and will be memorialized with a statue outside the Nationals' new ballpark.
A number of Negro Leagues players and their relatives were on hand for the occasion. The most prominent was Gibson's great-grandson, Sean Gibson, who threw out the first pitch, a soft strike to Nationals reliever Ray King.
Other Negro Leagues alumni on hand included Eddie Banks, James Bland, Mamie Johnson, Jose Piloto and James Tillman.
The St. Louis Stars played in the Negro Leagues between 1922 and 1931. Last year the Cardinals paid tribute by wearing Stars uniforms in a game against the Pittsburgh Pirates, who donned replica Greys uniforms.
Cardinals manager Tony La Russa has been a part of such tributes throughout his career, and always looks forward to them.
"I think it's very appropriate, that kind of tribute to that era of baseball," La Russa said. "I think we always enjoy it."
Friday also marked the anniversary of a historic occasion. On Aug. 3, 1948, Satchel Paige made his first start as a Major Leaguer, with the Cleveland Indians. His team defeated the Washington Senators that day. Paige was believed to be 42 years old at the time, but that didn't stop him from playing several more years, including one with the St. Louis Browns.
Friday's ceremonies concluded with Nationals third baseman Ryan Zimmerman receiving the 2006 Larry Doby Legacy award. He had been chosen for the award because of his outstanding rookie season.
Michael Phillips is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.