To compare, more than 84 million people watched the first debate between Trump and Clinton on 26 September 2016.
"An estimated 73.1 million people tuned in to watch the first debate of the 2020 presidential election on Tuesday, 29 September 2020", the release said on Wednesday.
The viewership for Tuesday's presidential debate is 13 percent less than the first debate between then-Republican presidential nominee Trump and his Democratic opponent Hillary Clinton in 2016.
Many viewers also criticised Fox News' anchor Chris Wallace, who acted as the moderator at the Tuesday debate and failed to provide for an orderly discussion, since both candidates constantly diverged from the main topics. President Trump repeatedly interrupted Biden, while the latter snapped at his opponent, calling him a "clown" and even told Trump to "shut up".
Trump and Biden discussed a wide range of issues, including the coronavirus response, healthcare in general, anti-police riots and racism, taxes, the environment, and the integrity of the upcoming election.
The next two presidential debates are scheduled for 15 October in Florida and 22 October in Tennessee. The vice-presidential candidates' only debate is set for 7 October in Utah.