Hillary Clinton said she agreed that Donald Trump is the "most dangerous person" to run for president in modern US politics.
Quoting failed Democrat nominee Bernie Sanders, Clinton said she thought "he is right" to believe Trump is dangerous.
Donald Trump accused Hillary Clinton of being behind allegations from numerous women who accused the Republican of sexual assault.
Trump claimed that the stories of him assaulting women had been "largely debunked".
"Those people, I don't know those people", Trump said.
"I have a feeling how they came - I believe it was her [Clinton's] campaign that did it".
Hillary Clinton mocked Donald Trump for hosting America's version of The Apprentice.
Speaking at the final presidential debate, Clinton compared her professional record to billionaire Trump's.
The Democrat said that while she was in Beijing advocating human rights in the 1990s Trump was "insulting" a former Miss World - calling her an "eating machine".
She added: "On the day that I was in the situation room, monitoring the raid that brought Osama bin Laden to justice, he was hosting the Celebrity Apprentice".
Donald Trump warned that America will find itself in "some mess" if Hillary Clinton becomes president.
"The problem is you talk, but you never get anything done, Hillary", Trump said during the final presidential debate.
The Republican then accused Clinton of letting $6 billion go missing when she was in charge of the State Department.
"$6 billion was either stolen - they don't know. It's gone", he said.
"If you become president this country is going to be in some mess".
Donald Trump insisted that Vladimir Putin is not his "best friend" as he spoke at the final US presidential debate.
Speaking about the US's relation with Russia, Trump said: "I don't know Putin. I have no idea.
"I never met Putin. This is not my best friend".
Donald Trump and Hillary Clinton accused each other of being "puppets" as they debated the US's relationship with Russia.
Trump said that he "didn't know [Vladimir] Putin" but claimed the Russian leader had "no respect" for Clinton or President Obama.
Clinton quipped back: "Well, that's because he'd rather have a puppet as president of the United States".
Trump responded: "No puppet. No puppet. You're the puppet".
Hillary Clinton accused Donald Trump of using illegal immigrants to build his headquarters Trump Tower.
The Democrat described bringing immigrants into the "formal economy" as a means of stopping employers from exploiting cheap labour.
Clinton said Trump knew "a lot about" using cheap labour as a way of undercutting American citizens' wages.
"He used undocumented labour to build the Trump tower", she said. "He underpaid undocumented workers and when they complained he basically said what a lot of employers do - 'you complain, I'll get you deported'".
Donald Trump promised to rid America of "bad hombres" coming over the border from Mexico.
Speaking at the final presidential debate against Hillary Clinton, Trump reiterated he would "build the wall" between the two countries in order to stop the flow of drugs across the border.
The Republican said one of his first acts as president would be to remove drug lords from America.
"We have some bad hombres here and we are going to get them out", Trump said of illegal immigrants.
The third and final presidential debate between Donald Trump and Hillary Clinton began without a handshake.
After Fox News host Chris Wallace introduced the two candidates, both Trump and Clinton walked to their podiums without shaking hands - and barely acknowledging each other.
Taking place in Las Vegas, the debate is the final head-to-head clash between Trump and Clinton before the US presidential election on November 8.