Lemel Leo Adler, 89, and Leon Schagrin, 85, reunited in Tamarac, Fla., Sunday, after not seeing each other for 70 years, the South Florida Sun Sentinel reported.
"This is the biggest, most important day of my life," Schagrin said.
Both cousins had been living in Broward County and searching for surviving family members with little luck, until recently.
Last week, a friend gave Adler a book Schagrin had written on his Holocaust experiences.
"I don't usually read such books, because I lived through the Holocaust," Adler said. "But then I started scanning it and found family names -- like my mother's maiden name."
Adler checked the facts at the South Florida Holocaust Documentation and Education Center and learned about Schagrin.
"I know you!" he told Schagrin in a phone call.
Such reunions are rare, now that the number of Holocaust survivors is dwindling, The Miami Herald reported.
Holocaust Survivors of South Florida, of which Schagrin is vice president, has only 400 members, down from 1,500 in the 1990s.
Miriam Fridman, president of the group, said she cannot remember a reunion like Adler and Schagrin's happening in the past.
"Most have either found their relatives, or they're six feet under," Fridman said. "So this is very unusual."
After their first meeting, Adler and Schagrin promised to meet again soon and to keeping sharing their memories.
"There's a lot to talk about," Schagrin said.