"I don't think there is very much to having a partial bid for the company, at least as a large shareholder," Icahn said.
Miller, according to a report by the Wall Street Journal, is trying to raise money to buy all or part of the company. That has not been confirmed and the New York Post says he is actually trying to raise money for other purposes.
Icahn said he spoke to Miller over the weekend about the possibility of buying Yahoo.
"I think the stock is very undervalued," Icahn said.
He said the board would have to listen to any offer for a high price, but he is not enthusiastic about a sale.
"Right now I would be against that and I pretty much told Jonathan that," Icahn said.
He said he had not spoken to others on the Yahoo board, but thought they would agree.
Yahoo chief executive Jerry Yang has agreed to resign, under pressure, following the collapse of a possible acquisition by Microsoft and poor performance.
Icahn said the company needs a new CEO who is "a hard-nosed, cost-cutting kind of guy."
He repeated his view that Yahoo needs to do a deal with Microsoft to share searching.