The bodies of two of the men, Lt. John Pritchard and Pvt. Christopher Elphick, were identified by jewelry, the Daily Mirror reported. Pritchard wore an identity bracelet and Elphick a signet ring.
The remains of their two comrades were buried as unknown soldiers.
Members of the Pritchard and Elphick families came to France to see their interment in the cemetery at Ecoust-St. Mein near Arras, about 2 miles from where the bodies were found.
Pritchard and Elphick were listed as missing in action in the Battle of Bullecourt on May 15, 1917. Both were members of The Honorable Artillery Company, founded by King Henry VIII and the oldest unit in the British army.
Didier Guerle said he found a gas canister when he plowed the field for the first time, four years ago, and then uncovered human bones. The aging farmer said his father had always told him not to plow that field.
About 300 people attended the ceremony, including Prince Michael of Kent, the Honorable Artillery Company's honorary colonel.
Pritchard's nephew, John Shell, 89, laid a wreath on his grave.
"It seems silly to say it but the feeling I had was that he is coming home," Shell said. "He isn't of course, but that was the feeling."
Elphick was survived by his wife and a young son. His grandsons were at the burial.
Christopher Elphick, 64, of Cross-in-Hand, East Sussex, his grandfather's namesake, said his grandmother and father never knew what happened.
"It means a tremendous amount to have this wonderful ceremony," he said. "We feel incredibly honored about this. It's putting an end to a mystery that has been with our family for almost 100 years."