An attorney for Kenneth Manzanares entered the plea during an arraignment in a federal courtroom in Juneau, Alaska. The judge presided via a video link from Anchorage.
Manzanares, clad in a yellow prison uniform, dabbed his eyes as the indictment against him was read.
Prosecutors have not decided if they will seek the death penalty. A hearing on that issue is expected later this year.
Manzanares was indicted by a grand jury last week in the death of his wife, Kristy Manzanares, a 39-year-old real estate agent.
She was found July 25 in a cabin on a Princess Cruises’ ship while it was in U.S. waters off Alaska. The ship, which had left Seattle on July 23 for a seven-day roundtrip cruise, later docked in Juneau for the investigation.
A neighbor of the couple told The Associated Press last month they had booked the cruise to celebrate their anniversary.
FBI Special Agent Michael Watson said in an affidavit that witnesses saw Manzanares with blood on his hands and clothing. One said Manzanares told him: “She would not stop laughing at me,” according to the affidavit.
During an FBI search, Manzanares “spontaneously stated, ‘my life is over,'” Watson said.
[Image via Princess Cruises screengrab]