Sources told CNN that Rudy Giuliani met with the House committee for nine hours on Friday.
The former lawyer for Donald Trump was subpoenaed in January for trying to convince state legislators to overturn the election results.
Giuliani was scheduled to testify earlier this month, but backed out after his attempt to record the meeting was rejected, his lawyer told CNN.
Both sides continued to negotiate a meeting date, which eventually led to Friday's deposition.
Giuliani promoted a false claim that the 2020 election was stolen from Trump. After the election, he helped Trump file federal lawsuits against states.
He promoted baseless claims of election fraud, including claims that poll workers were adding fake ballots to the election count and that election-technology company Dominion was behind Trump's 2020 loss.
Representatives for Giuliani and the House Committee did not reply immediately.