Barr's testimony before the committee's 40 members marks his first time appearing before the Democrat-led panel.
The U.S. Senate has acquitted President Donald Trump of impeachment, ending only the third presidential trial in American history with votes that split the country and tested civic norms.
Pushing ahead with articles of impeachment, the House Judiciary Committee convenes Monday to formally receive the investigative findings against President Trump as the White House mounts an aggressive attack on the proceedings.
The House has passed a civil contempt resolution that allows committees to sue the Trump Administration and enforce Congressional subpoenas.
The top Democrat on the House Judiciary Committee says he believes it would be an "impeachable offense" if it's proved that President Donald Trump directed illegal hush-money payments to women during the 2016 campaign.