The BBC's team of correspondents log their impressions, reports and pictures as they watch events unfold at the Iowa caucuses.
Most recent postings are at the top.
Ian Pannell :: Des Moines, Iowa :: 0640GMT
The turnout was very good for Iowa. The population here is just short of three million. Of that 120,000 turned out for this vote. That is double the turnout in 2000 when Gore was seeking the nomination.
In terms of the democratic party, they are getting excited and I have some sense they have a real fire in their belly for beating George Bush.
Now it is on to New Hampshire already the campaign bandwagon is de-rigging and on it's way out of town. The candidates are already on their way there now.
Rob Watson :: Des Moines, Iowa :: 0320GMT
In the end it was Senator John Kerry's night. Though only a few weeks ago his campaign appeared to be floundering, the Vietnam war hero emerged the clear winner with his support at 38%.
There was also a very good result for the South Carolina Senator John Edwards with Iowans clearly warming to his southern charm and positive message.
The biggest upset was the third placing for former Vermont governor, Howard Dean. His outspoken opposition to the war in Iraq and his ability to excite younger voters had made him the early favourite.
The race for the Democratic Party nomination is far from over but the result here is clearly a major boost for Senators Kerry and Edwards.
Although the latest opinion polls still show Howard Dean leading in the next contest in New Hampshire next week, his campaign has got some major rethinking to do in the days ahead.
Ian Pannell :: Des Moines, Iowa :: 0300GMT
Hundreds of people have gathered at the campaign party for Senator John Kerry of Massachusetts who has been declared winner of the 2004 Iowa caucus.
The mood here is jubilant as people dance in the conference hall to the strains to We Are Family, by Sister Sledge.
Every minute, streams of Kerry supporters pour into the hotel where the reception is being held, to share in his surprise victory.
Until a few days ago, common wisdom held that the election would go to former Vermont Governor Howard Dean or Congressman Dick Gephardt of Missouri.
Over the last few days, Iowans seem to have gone for a safer bet in the Vietnam veteran.
John Kerry is expected here in the next hour, where he will be greeted by hundreds of ecstatic supporters.
Ian Pannell :: Des Moines, Iowa :: 0210GMT
The final results are in in precinct 68, Callanan Middle School in Des Moines.
John Edwards has 83 votes and John Kerry is in second place with 76 votes.
In a surprise result, third place went to Dennis Kucinich.
Under the complex caucus rules, all three candidates will be awarded three delegates to the national convention this summer.
Despite the late surge for Edwards, the biggest surprise of the evening here, came in the collapse in the vote for both Howard Dean, the doctor from Vermont, and Richard Gephardt.
Ian Pannell :: Des Moines, Iowa :: 0150GMT
Another count has taken place at Callanan Middle School. John Edwards's vote has gone up to 78, John Kerry's to 75, Dennis Kucinich's to 47 and Howard Dean's to just 21.
Final negotiations are now under way to persuade the last remaining voters, as the vote remains perilously close.
Ian Pannell :: Des Moines, Iowa :: 0115GMT
I am at Callanan Middle School on the outskirts of Des Moines, where 221 people have gathered to vote. They have split into different parts of the school hall to indicate which candidate they are supporting.
So far this is entirely unscientific. But the bulk of support here is split between John Kerry, senator for Massachusetts and John Edwards of North Carolina.
The votes so far: John Kerry 68, John Edwards 62, Dennis Kucinich 34, Howard Dean 27, Richard Gephardt 14, Wesley Clark 6.
Because of the caucus rules, people who supported candidates who got less than 15% of the vote will now have to move their support to one of the other candidates before a final declaration is made.
Sometimes chaotic and invariably off-the-cuff, this is raw democracy in action, warts and all.
Kevin Anderson :: Des Moines, Iowa :: 0030GMT
The campaigns made their last minute pitches in the hopes of getting the remaining undecided Iowans to swing to their cause.
But the final day of campaigning did not go well for all candidates. John Kerry lost his voice and had to cancel most of his campaign appearances, and Howard Dean lashed out at the press after they swarmed him at an appearance. He decided to leave early, but not without a parting shot, telling the press to "get a life."
Many Democrats were undecided as the caucus opened
Now, Iowans across the state are gathering for the caucuses. In churches, schools and even some homes, they are gathering with their neighbours to register their support for their candidates.
There were still some undecided voters, even as the caucuses began. Roger Schoonover of Des Moines started off as a Gephardt man, he says because of the candidate's strong support of unions.
Then he swung to Howard Dean before being put off by the candidate in the last debates.
"He was like it was either my way or no way at all," he said.
Tonight, he will to listen to his neighbours before he decides whether to support John Kerry or John Edwards.
Mishal Husain :: Des Moines, Iowa :: 2105GMT
There's just about three hours to go now before Democrats from across the state of Iowa will gather to debate upon, and to vote on the Democratic presidential candidates in this years election.
This is the contest which traditionally kicks off the US election year. Up to 100,000 voters are expected to take part. And this time around the contest looks like the closest in Iowa history.
Katty Kay :: Des Moines, Iowa :: 1950GMT
For about a day Iowans become kingmakers. There's a huge amount of media attention, all the political circus flies into town, then it all disappears again tomorrow after this caucus race is over.
It's not totally representative. This is quite a rural state; there aren't very many minorities here. So people say "Why Iowa? It's not representative of the rest of America."
But 100,000 people is still a pretty good straw poll. If you're going to try and take the pulse of the Democratic Party then this is a good place to start.
The process has to start somewhere and it gets the momentum going. Come out of Iowa doing well and you suddenly begin to look like a serious presidential candidate.
Kevin Anderson :: Des Moines, Iowa :: 1915GMT
Howard Dean could have used a couple of the members of the English rugby team today to block for him as he tried to negotiate a crushing media scrum in Des Moines.
His handlers barked at a crowd of some 50 TV cameras and their crews to back away from the campaign bus. "Take two steps back or we're not coming. We've got all day and it's cold out here," a Dean campaign staffer said.
Mr Dean's attitude towards the press is reputedly only slightly warmer than the chilly Iowan weather. When he did emerge from his bus, the cameras surged forward despite the staff's attempt to create a makeshift rope line.
The swarm followed him up steps, with sound crews and camera operators throwing elbows and jockeying for position. One cameraman fell as he tried to back-pedal.
Mr Dean's appearance threatened to overwhelm a state observance of Martin Luther King Jr day. Organisers of the event had invited all of the candidates, but they only found out that Mr Dean would attend when it was announced in the local newspaper.
Shortly after they arrived, a Dean campaign staffer announced, "Dean people, we're outta here."
The crush of media attention did not impress the home-town crowd. One woman left in disgust before the observance saying "They need to make some room for Iowans."
Iowa Governor Tom Vilsack told the crowd, "If the national media spent a little more time in Iowa, maybe they would learn to be more polite and more respectful."
Rob Watson :: Des Moines :: 1745GMT
It's expected that as many as 100,000 Iowans will brave below-freezing temperatures to express their preference for a Democratic Party challenger to George W Bush.
All of the four main candidates have relatively similar policies, so what's likely to decide the issue is who the voters here think has the best chance of beating President Bush in November.
Also important is organisation. Over the next few hours the campaigns will be knocking on doors and working the telephones to ensure their supporters turn out.
Jeremy Cooke :: Des Moines, Iowa :: 1710GMT
After months of campaigning, dozens of polls and endless political analysis, election season in Iowa reaches its climax tonight.
Supermarket stop for John Edwards
The caucus is a complicated procedure involving open debate and discussion in each location. The caucus ends with each meeting splitting up into groups, the size of which indicates the level of support for each candidate.
It is a close race which may well be decided by which candidate most successfully gets out most of the vote, among temperatures of -14C.
Kevin Anderson :: Des Moines, Iowa :: 1600GMT
A crowd of John Kerry's supporters in the small town of Norwalk will probably be disappointed to find out their man won't be appearing this morning.
Mr Kerry has lost his voice and is going to try to recuperate during the day and hopes to make campaign appearances late this afternoon.
The enthusiastic crowd was sandwiched in-between the video rentals and the deli at a local supermarket. Although he won't appear, his supporters were obviously cheered at his rise in the polls but on caucus day Mr Kerry did not want to be called the front-runner.
He held that mantle early on in the race only to struggle most of last year. But a late surge promises a surprisingly strong showing for Mr Kerry in Iowa.
Kevin Anderson :: Des Moines, Iowa :: 1440GMT
John Edwards left his hotel in downtown Des Moines just as the sun was rising. Already his supporters, as well as supporters of Howard Dean and a few of Dick Gephardt, stood on the street corners, braving the frigid morning to support their candidate.
Mr Edwards made his first campaign stop of the day at a local supermarket. The world's media have flocked to Iowa, and press photographers crowded behind the coconuts for the best shot.
Standing in front of the vegetable cases, the candidate who grew up in the segregated South told the audience about how he has and would fight for racial equality.
It is a standard part of his stump speech, but it is a message all of the candidates are giving on Martin Luther King day, the national holiday honouring the slain civil rights leader.
Candidates have been campaigning across the state for months
Mr Edwards has surged in the polls just weeks ahead of the caucuses, and his supporters can sense the momentum. Mr Edwards spoke for only about 15 minutes. The candidates are trying to pack in as many campaign appearances as possible on this caucus day.
Katty Kay :: Des Moines, Iowa :: 1200GMT
It is really important for candidates to do well in Iowa which is why they've all been spending so much time here, why they are really fighting for every single vote.
This is the first bite of the cherry for the candidates and whoever does well here gets the benefit of momentum, more money, more endorsements and they can carry that into the next stages of the primary.
All of America will be watching Iowa because it's the first chance to see what Americans think of their Democratic candidates, what they think of George Bush, what they think of the issues and who they think is the most electable amongst these candidates.
Going to rallies here in the last couple of days, what has really struck me is that Democrats here in Iowa and all over America
are really looking for the person who they think can go head to head with George Bush in the key election, the presidential election, in November.