House Republicans are questioning Comey on decisions made by the Justice Department during the 2016 presidential election.
Republicans will also focus on alleged political bias by Obama-era Federal Bureau of Investigation officials and potential FISA court abuses.
House Republicans are interviewing James Comey behind closed doors Friday, hauling the former Federal Bureau of Investigation director to Capitol Hill one final time before they cede power to Democrats in January.
But Comey relented to the closed-door interview after gaining a promise that a transcript of the session would be released to the public after 24 hours.
"Without the phony Russia Witch Hunt, and with all that we have accomplished in the last nearly two years (Tax & Regulation Cuts, Judge's, Military, Vets, etc.) my approval rating would be at 75% rather than the 50% just reported by Rasmussen", Trump wrote in his tweet.
Citing a poll that has in the past given him more generous numbers than others have, President Donald Trump on Thursday tweeted that he'd have an even higher approval rating were it not for the Russian Federation investigation being led by special counsel Robert Mueller.
Comey was in charge of both of those investigations.
The interview is expected to last much of the day.
President Donald Trump, speaking behind a microphone during a press conference at the White House. Mueller took over the department's investigation when he was appointed in May 2017.
House Republicans have faced criticism - even from GOP Oversight Chairman Trey Gowdy, who is co-leading the effort - throughout their probe for breaking confidentiality agreements and selectively leaking portions of witnesses' answers that are often misleading without proper context.
"Don't do it in a dark corner and don't do it in a way where all you do is leak information", said Comey's attorney, David Kelley.
The report said the former Federal Bureau of Investigation director, who announced in July 2016 that Clinton had been "extremely careless" with classified material but would not be charged with any crime, repeatedly departed from normal Justice Department protocol.