A 40 percent contingency fee negotiated by a Manhattan law firm retained by the widow of a real estate developer involved in a multimillion-dollar estate dispute was not "unconscionable on its face," an appeals court ruled yesterday.

The court said that "at first blush," the 40 percent fee — worth about $42 million — that was claimed by the law firm, Graubard Miller, from Alice Lawrence, the 83-year-old widow of the real estate developer Sylvan Lawrence, "might arguably seem excessive and invite skepticism."

But a majority of the five-member panel of the court, the Appellate Division of State Supreme Court in Manhattan, ruled that whether the fee was reasonable should be determined at a trial, based on a further exploration of the discussions that led to the fee agreement and the difficulty of the case.

In a dissent, one justice, James M. Catterson, called the fee "exorbitant." He said that the retainer agreement was signed when a $60 million settlement offer was already on the table.

The estate was settled just five months later for more than $100 million, the judge said, meaning that the law firm's fee was almost equal to the additional amount it won.

Mark Zauderer, a lawyer for the firm, said in a telephone interview that Graubard Miller was delighted with the decision, which was issued in response to Mrs. Lawrence's appeal of two decisions in Surrogate's Court.

Mr. Zauderer said that the fee had been justified by the law firm's success in winning about $115 million for Mrs. Lawrence against Seymour Cohn, her husband's brother, business partner and executor — against an adversary who, he said, was "extremely wealthy and well defended."

"What the courts recognize is that a fee agreement is not unconscionable simply because it can produce a big fee," Mr. Zauderer said. "You have to look at the value rendered to the client."

Leslie Corwin, Mrs. Lawrence's current lawyer, said there was a "strong possibility" that she would seek to have the Court of Appeals hear the case.

Mr. Lawrence died in 1981. At the time, he and his brother owned "more than 90 commercial buildings and parcels of real estate," the dissent said. Mrs. Lawrence wanted to sell them. Mr. Cohn, who died in 2003, opposed her.

"This is now the third time a court or a judge has affirmed the right of the Graubard firm to be paid a well-earned fee in which it got a tremendous result in a highly complex case," Mr. Zauderer said.