With the world's financial markets watching, Yellen, who succeeded Ben Bernanke last week, will have a chance to set a mostly upbeat tone and point to signs of steady economic progress, despite some recent bumps in the road.
The Fed has embarked on perhaps its most difficult policy shift after five years of ultra-easy money. It has begun scaling back its bond-buying stimulus, but at a measured pace that could frustrate some Republicans who think the programme is reckless.
Those concerns will be aired on Tuesday, when Yellen appears before the Republican-controlled House Financial Services Committee to testify on the Fed's semi-annual monetary policy report. Her testimony will be released at 8.30 am (1330 GMT), although the hearing does not begin until 10 am (1500 GMT).
She testifies to the Democrat-controlled Senate Banking Committee on Thursday.
The Fed has trimmed its asset purchases twice since December, encouraged by momentum in the economy late last year. But two months of weak US jobs growth, a slump in manufacturing and a recent sell-off in emerging markets now complicate things for the new Fed chief.
Underlining Republican unease with the Fed's aggressive response to the financial crisis and recession, the House panel invited witnesses to react to Yellen's testimony immediately afterwards. Three of the four are critics of the bond-buying programme, including Stanford University's John Taylor.
Conservatives worry the years of near-zero interest rates and trillions of dollars in money-printing risk weakening the US dollar, while setting the stage for asset price bubbles and an explosion in inflation.
Jeb Hensarling, chairman of the House committee, has been holding hearings on the asset purchases, which are currently running at $65 billion per month. In the Senate, fellow Republican Rand Paul wants to establish audits of the Fed's policy deliberations a notion Bernanke and others have slammed as a threat to central bank independence from politics.
Another Republican panel member, representative Shelley Moore Capito, said Yellen must do more to help senior citizens build safe investment returns. No one can create any wealth with interest rates squashed as they are, she said.
For all the criticism, most economists blame Congress for slowing the US recovery from recession with cuts to government spending, tax increases and a series of budget battles that tested investors' confidence in the US.
Capito said that while she would like Yellen to give more specific answers to questions than her predecessor did, the new chair will likely be spared the contentious jabs Bernanke took from committee Republicans.
She will be treated respectfully, Capito said. I don't think there will be a lot of fireworks.