That concludes a day of high drama on Capitol Hill.
It's a blow for the president but he has vowed to push ahead with his agenda.
Influential conservative website Breitbart writes:
Republican officials in Congress and the White House are now openly discussing finding a GOP replacement to Rep. Paul Ryan (R-WI) as Speaker of the House, after Ryan failed to pass the American Health Care Act out of the House and misled the public and President Donald Trump when he promised repeatedly the bill would pass.
The Federalist writes:
Yes, AHCA failure is a failure for the president, but it’s much more a failure for House leadership and Paul Ryan. They had seven years to prepare for this moment, and they failed to do so sufficiently.
A rally is going on outside Congress by activists who want to protect Obamacare and oppose the Republican efforts to reform the healthcare system.
The BBC's Daisy Walsh is talking to people there.
BBC North America reporter
For the first time in 11 years, Republicans control the presidency and both chambers of the Congress.
There are 44 more Republicans than Democrats in the House of Representatives.
Republicans have been vociferously calling for repeal of President Barack Obama's healthcare reforms for seven years.
The American Health Care Act was the first major piece of legislation pushed by the White House and the Republican-controlled Congress, a key political test early in the president's term, when he should be at the height of his power and party cohesion at its strongest.
In spite of all of this, Mr Trump, House Speaker Paul Ryan and the Republicans running Washington could not get the job done.
For Republicans Friday wasn't just bad. It was a disaster.
The Dow Jones had been leaking all day on uncertainty over the health care vote - then rallied when that uncertainty ended.
John Mervin, BBC business, New York, writes:
In the event, Donald Trump and the GOP's failure to repeal Obamacare, doesn't seem to have bothered investors too much. The Dow Jones Industrial Average fell 60 points on Friday, pulling back some of its earlier losses as news came out that the bill was being pulled.
More than events themselves, it's unexpected events that tend to spook financial markets, hence the lack of a freak-out at this undeniably big moment for the Trump administration.
It's also true that markets have always been more concerned with other parts of President Trump's economic agenda, namely his plans to cut regulations and taxes. Some people clearly think that repealing Obamacare was an unhelpful distraction from that, and now it's apparently not happening, the thinking goes, the Republicans can get on with plans they can carry out. Indeed some feel this quick failure is preferable to a bill passing the House only to get bogged down in further months of recrimination and bad PR in the Senate.
But that all presupposes tax cuts will now be easy. What if they're not? What if the failure of healthcare bill is simply the first part of a wider unravelling of Republican plans? In that case, the investor freak-out about a failure of Trump's economic agenda hasn't been avoided. It's just been delayed.
Mr Trump said he was open to redrafting a new bill after the existing law "explodes".
The Congressional Budget Office (CBO), which does the US government's analysis, said that Obamacare is looking stable.
But Republicans say the CBO is not making accurate predictions and President Obama's signature health law is in a "death spiral" of rising premiums and dwindling insurance options.
Hillary Clinton has sent out a series of tweets hailing the failure of Trumpcare - and praising the way, she says, Obamacare has helped Americans.
She posted a tweet saying there was "no substitute for standing up and defending our values" and then six case studies of those who had benefited under Obamacare:
Republican representative Louie Gohmert said Mr Trump had done "amazing work" on what was a bad bill.
Imagine what he could do with a good bill, he said.
He told the BBC's Laura Bicker he had not seen Mr Trump work before but was hugely impressed and that this augured well for the future.
Here is Trump from a little earlier, telling reporters where the bill stands now.
And Paul Ryan describes the difference between being an opposition party and a governing one.
Democratic representative Keith Ellison has told his party not to gloat.
He said: “The only reason [the bill] failed is because a number of Republicans felt that it did not do enough damage.
“However, they will try again. Democrats, grassroots activists, and millions of Americans who don’t want to lose their coverage must be ready to mobilise like never before.”
Ron Christie, a member of former vice-president Dick Cheney's staff, told the BBC this defeat was not a question of "growing pains" as Paul Ryan had put it, but a disaster for the party.
"The Republicans had seven years and today they blew it," he said.
His advice to Mr Trump?
"The next time Republicans seek to put a major piece of legislation on the floor, talk to the entire caucus so that this sort of embarrassment doesn't happen again."
If you're just joining us and missed this a little earlier... here's Speaker Paul Ryan giving his "un-sugarcoated" assessment.
The Huffington Post tweets its obit to Trumpcare:
Trump offers an olive branch - and a nettle.
"Just remember - this is not our bill. This is their (Democratic leaders') bill. Now when they all become civilised and get together and try to work out a great healthcare bill for the people of this country, we're open to it."
President Trump continues: "I really believe a better bill will come out of it - both parties can get together. Bipartisan would be a big, big improvement. I think it will end up being a very good thing."
He also said he had never claimed he would repeal and replace Obamacare within 64 days.
President in the White House: "What would be really good, with no Democratic support - if the Democrats, when it explodes, which it will soon - if they got together with us and got a real healthcare bill. I'd be totally open to it."
On Obamacare: "It's imploding and soon will explode, and it’s not going to be pretty.
"And so the Democrats don’t want to see that. So they’re gonna reach out when they’re ready, and whenever they’re ready, we’re ready."
Trump in the White House now: "I've been saying for the last year and a half that the best thing we can do politically speaking is let Obamacare explode. It is exploding right now."
The longtime Republican plan to "repeal and replace" Obamacare has suffered a crushing blow today.
Republicans Senator Lindsey Graham is ready for Plan B, which he says will begin with the failure of Obamacare.
Donald Trump says Republicans will probably work on tax reform now, CNBC quotes him as saying.
Kevin Brady, the Texas Republican who chairs the House Ways and Means Committee, tells Fox News that Trump must move on directly to tax reform.
The Washington Post writes:
"Friday's scheduled vote on a Republican health-care overhaul represented the first major test of Trump's ability to cut deals as president. He failed the test.
A last-minute decision to scuttle the vote spared Trump the indignity of a formal defeat, but the move amounted to a loss via forfeit. In a press briefing earlier Friday, White House press secretary Sean Spicer reminded reporters that the president had personally lobbied 120 lawmakers in meetings or phone calls.
Spicer said Trump had “left everything on the field,” but “everything” proved insufficient."
"This bill went down today," House Democratic Whip Steny Hoyer says, because the majority of Congress thought it was the wrong bill.
He condemned Republicans for trying to remove "essential services", such as maternity care.
Democrats are now taking their turns at the podium to rejoice at the bill's failure.
Donald Trump predicts that Obamacare "will explode".
Associated Press quotes president as saying he would be "open" to tackling health care again if "Obamacare" law implodes.
Republican Representative Steve Womack: "We are going to have to re-educate ourselves in mathematics."
House Democratic leader Nancy Pelosi is cock-a-hoop.
At a press conference, she says: "Today is a great day for our country. It is a victory for the American people."
"Again, this is pretty exciting for us... a victory for the Affordable Care Act."
If you're just joining us, Paul Ryan's news conference is over - he's had better days...
Here's his quotes...
"Moving from an opposition party to a governing party comes with growing pains, and, well, we're feeling those growing pains today. We came really close today, but we came up short. I spoke to the president just a little while ago and I told him that the best thing I think to do is to pull this bill, and he agreed with that decision.
"I will not sugar coat this, this is a disappointing day for us. Doing big things is hard."
"Yes this does make tax reform more difficult," Ryan says, referring to the next major agenda item for Trump.
But he vows: "We are going to proceed."
Ryan: "Obamacare is going to be getting even worse. Actually, I think we were going to be doing the Democrats a favour, we were doing the architects of Obama [sic] a favour by passing this law before it gets even worse."
The House Speaker, usually ice cool, speaks in rapid fire tones. We've never seen him so agitated.
"We just didn't quite get consensus today," Ryan says.
"We came very close.
"That's why I thought the wise thing to do was not proceed with the vote, but to pull the bill."
"I’m really proud of the bill we produced."
"The worst is yet to come with Obamacare", he adds, thanking the president, saying that he "gave his all in this effort".
Paul Ryan: "We've got to do better and we will. This is a setback no two ways about it."
"Moving from an opposition party to governing party comes with growing pains," Paul Ryan says, admitting that today they "came up short".
Donald Trump is due to give a statement from the Oval Office.
Paul Ryan says: "I will not sugarcoat this. This is a disappointing day for us. Doing big things is hard."
New York Democrat Sean Maloney and his chums are gleeful.
The link in the tweet below will take you to Paul Ryan's press conference, due any moment.
Washington Post reporter Robert Costa has been telling MSNBC about the 15-minute phone call he had with President Trump as the bill collapsed.
Costa said his key takeaway was that here's a president adjusting to Washington and very frustrated about this but aware he has to figure out a way forward.
The president said he felt he had done everything he could to get the bill through, and laid no blame at Speaker Paul Ryan's door.
But he wants to do tax cuts very soon, added Costa.