According to the results of of vote counting, Biden received 306 electoral votes (270 electoral votes were needed to win). Kamala Harris has been confirmed as the next Vice President.
Biden will be inaugurated on January 20.
Some Republican lawmakers' objections to overturn the result in Arizona and Pennsylvania were rejected. The session certified Mr Biden's 306 votes to Mr Trump's 232.
As we reported earlier, four people died during violent pro-Trump protests at the US Capitol on Wednesday night.
One woman was shot by police, while three others died as a result of "medical emergencies", officials said.
The mob, which had been encouraged by President Trump, stormed the building in a bid to overturn the election result, suspending a Congress session.
The president-elect blasted the "insurrection".
President Donald Trump later called on them to "go home" while continuing to make false claims of electoral fraud. Twitter and Facebook later froze his accounts.