Authorities reported one minor injury in the blaze that started just before 7 p.m. at the Serbian Orthodox Cathedral of St. Sava in Manhattan.
Three hours later the main body of the fire was knocked down, but firefighters still were putting out small pockets of flames, officials said. Authorities did not say what caused the fire.
A church priest, Father Djokan Majstorovic, says he felt like he was "in a nightmare" as he tried to get to the fire scene that was blocked off by firefighters.
The fire completely destroyed the roof of the Gothic Revival style building. It broke out on the same day Orthodox Christians around the world celebrated Easter. The church website listed services that morning and an Easter luncheon at 1 p.m.
"Heartbroken. I was just inside that building three hours ago," Dex Pipovic told PIX11 News. He said he had been going to the church for the past seven years.
The church was designed by architect Richard M. Upjohn and was built in the early 1850s. One of its earlier congregants was novelist Edith Wharton, who wrote "The Age of Innocence." She was married in the church in 1885.
The Serbian Orthodox Church purchased the building from the Episcopal Diocese in New York in 1943. The building was designated a city landmark in 1968.