Mnuchin, speaking at the Delivering Alpha conference presented by CNBC and Institutional Investor, said he has been working with President Donald Trump on filling the Fed chairman position. Yellen's term expires early next year.
Trump has said White House economic advisor Gary Cohn is a candidate, but Mnuchin would not comment specifically on whether Cohn is still being considered.
"I obviously will respect the confidentiality of the process and not make any comments on any specific people that the president is considering," said Mnuchin. The White House has a number of empty Fed seats to fill, including that of Fed Vice Chair Stanley Fischer who resigned last week.
Trump reportedly has become unhappy with Cohn, after the director of the White House Economic Council publicly rebuked the president for his reaction to violence in Charlottesville, Virginia.
But Mnuchin did comment on the fact that Yellen remains under consideration.
"I'm working closely with the president on the issue. He hasn't made any decisions and that's one of the things he's still considering," said Mnuchin
"There's a lot of good people. The chair is obviously quite talented, and she's being considered, but there's a lot of great people that we've been meeting with and considering as well."
Mnuchin would not comment on Cohn's relationship with the president. In response to a question about his relationship with Cohn, Mnuchin said the two have been working closely together on taxes, and would be meeting with the president at dinner on Tuesday night.
"Let's me just say, you know I appreciate working with him," said Mnuchin, who had worked with Cohn at Goldman Sachs.
Former Fed Governor Kevin Warsh is also reported to be under consideration for the Fed chair.