Party: The Republicans - They're a bit like the Conservatives in the UK
Family: Married to Cindy, with 7 children
Fave songs: Dancing Queen by Abba
He first tried to be the Republican candidate back in 2000, but his party chose George Bush instead.
Before getting into politics, he was a pilot in the American Navy.
In the 1960s, his plane was shot down during America's war in Vietnam and he was captured and held prisoner for five-and-a-half years.
When he was released he was given medals for bravery and made an American war hero.
He says climate change is real and devastating and he's willing to spend more money on trying to sort it out.
He also thinks America should consider joining with every other nation in the world to reduce greenhouse gas emissions, if China and India join in.
War in Iraq:
McCain was in favour of the war in Iraq and if he wins he says he'll keep American troops over there for as long as they're needed.
Will he win?
If he does, he'll become the oldest new President America's ever had.
He says his age means he's got lots of experience and reckons that right now that's what America needs most.
But winning won't be easy as McCain has been falling behind Obama in the polls in recent weeks.
Party: The Democrats - They're like America's version of the Labour Party
Family: Married to Michelle, with 2 daughters
Fave songs: Ready Or Not by The Fugees
He is the first black candidate to become the presidential candidate of either major American party.
His mum's American, his dad is African and he was born on one of the American islands of Hawaii.
He also lived in Indonesia, in south east Asia, for a while as a child.
After studying law at one of the country's top universities, he worked as a lawyer for people's rights before getting into politics.
He wants America to lead the way in the global effort to tackle climate change, including slashing America's greenhouse gas emissions by a whopping 80% by the year 2050.
He also says he will invest a staggering $150billion (about £100 billion) over 10 years in clean energy.
War in Iraq:
Obama was against the war in Iraq and if he wins he says he'll pull out all the American troops within 16 months.
Will he win?
If he does, he'll become America's first black President.
As little as 50 years ago, African Americans didn't have the same rights as everyone else and in some places, black and white children weren't even allowed to go to the same schools.
Although racism is still a problem in some parts of America, lots of people think that if Obama can win the election it would show the rest of the world how much America has changed.