With 66 percent of precincts reporting, Gregoire - the state's first female attorney general and one of the leaders of the $206 billion tobacco settlement in the 1990s - had more than two of every three votes.
She picked up 243,563 votes, or 68 percent, compared with 94,154 votes, or 26 percent, for Ron Sims, the state's most prominent black politician and the leader of Washington's largest county, home of Seattle.
A jubilant Gregoire said: "People want our economic engine fired up again. ... They want someone who will lead them in the right direction."
In the nation's capital, former- infamous for being caught on an FBI video smoking crack during his third term - won the Democratic nomination to a city council seat in his second comeback since his drug conviction. In the strongly Democratic city, a fall victory is virtually guaranteed.
The full slate of primaries also saw a handful of contested House and Senate seats. Other states voting were Massachusetts, Minnesota, New Hampshire, New York, Rhode Island, Vermont and Wisconsin.
In Washington state and Wisconsin, two states considered battlegrounds for the presidential race, Republicans who will be challenging Democratic senators in the fall made the war on terror and their support for President Bush central to their campaigns.
With the GOP's narrow 51-48 control of the Senate at stake, races in both states are receiving national attention and money.
In Wisconsin, former Army Ranger Tim Michels, who won the GOP nomination to challenge two-term Democratic Sen. Russ Feingold, ran an ad that featured the World Trade Center on fire.
In Washington state, five-term Rep. George Nethercutt swept past five other Republicans to challenge Sen. Patty Murray, who easily won the Democratic nomination for a third term.
"She's going down and we're going up. The differences between us couldn't be clearer," Nethercutt said.
Murray called Nethercutt a rubber-stamp for Bush and the Republicans who run Congress and said he is out of the mainstream.
The wide-open race for Washington's governor - two-term Democratic Gov. Gary Locke chose not to seek re-election - also set off a divisive contest.
Dino Rossi, a former state senator, easily won the GOP nomination. But while Gregoire dominated in the polls and money leading up to the primary, leaders of the Seattle black community criticized her for belonging to an all-white sorority in the 1960s.
Gregoire accused Sims of planting the story and said he knew full well that she is not racist. She argued that she helped get the sorority's racial policy reversed. "Knock it off, Ron!" Gregoire shouted at an August speech, her voice shaking with anger.
Sims denied any role in the story. Sims - the King County executive for the last eight years - made news with a proposal for a state income tax, coupled with elimination of the business and state sales tax.
The primary was the state's first without the longtime "blanket" primary that allowed voters to choose nominees from all political parties. Now, candidates appear on separate ballots divided by party, and voters have the choice to decide which party's ballot to cast.
In New England, five-term Democratic Sen. Patrick Leahy of Vermont easily won his nomination, as did two-term GOP Sen. Judd Gregg of New Hampshire. So did two first-term GOP governors - Vermont's James Douglas and New Hampshire's Craig Benson.
Elsewhere, Democratic Sen. Chuck Schumer of New York had no primary opposition.
In the fall, New Hampshire's Gregg will face Democrat Doris "Granny D" Haddock, 94. She walked across the state for this campaign.
In contested House races, longtime GOP Rep. Sherwood Boehlert of New York beat back a conservative challenger who had nearly defeated him two years earlier. In a Democratic district in Brooklyn, Rep. Major Owens easily won a three-way primary.
In Wisconsin, Gwen Moore, the first black woman elected to the state Senate, won the Democratic nomination for an open Milwaukee-area House seat. Gerald Boyle, a Marine reservist who served in Iraq, won the GOP nomination.
Other competitive House races included the eastern Washington seat that Nethercutt left open by running for the Senate. He made history in 1994 by defeating then-House Speaker Tom Foley, a Democrat who had represented the district for 30 years. Conservative state Rep. Cathy McMorris won the nomination and will take on Democrat Don Barbieri, chief executive of a hotel company.
A Republican-dominated district in Seattle's suburbs saw the law officer who caught the Green River serial killer, Sheriff Dave Reichert, leading three Republicans for the seat left open by retiring Rep. Jennifer Dunn. Reichert had 48 percent of the vote with 33 percent of precincts reporting.
By Robert Tanner