Kim Albanese Gotti, 41, waved to her husband as she sat with other supporters in Manhattan Federal Court Wednesday while his lawyers tried to discredit the government's star witness, the New York Daily News reported.
She repeatedly shook her head to signal disbelief as John Alite, a veteran Gambino crime family associate, testified against the 45-year-old Gotti.
She offered no comment after the day's proceedings.
Gotti is accused of racketeering for a fourth time and has been behind bars for a year.
At one point, Judge Kevin Castel accidentally called Gotti lawyer Charles Carnesi "Mr. Carneglia." Charles Carneglia is a Gambino associate convicted of a 1983 killing. The judge apologized to Carnesi.
Gotti's father, mob boss John J. Gotti, died in prison in 2002.