A second group was scheduled to gather Sunday at the same resort hotel at Mount Kumgang on the east coast of North Korea, South Korea's Yonhap news agency reported. About 360 South Koreans were expected to cross the border.
The partition of the Korean peninsula after World War II and the Korean War, which ended in a truce in 1953, split many families with parents being separated from their children and siblings from each other.
Kim Sum-kyong, 91, was so frail he had to travel to Mount Kumgang in an ambulance for a reunion with his daughter and to return to his home in South Korea a day early.
"Father, please don't die, and let us meet again when the two Koreas are reunited," Kim Chun-soon told him as they parted.
Hwang Deck-young, who was drafted into the North Korean Army during the war but ended up in South Korea, saw his two younger sisters for the first time in more than 60 years.
"Now, my wish has come true. I have no regrets even if I die tomorrow," Hwang, 82, said.
Plans for family reunions were first announced in 1988, Yonhap said. The South Korean government says that more than 129,000 of its citizens applied to participate -- and 40 percent of them have since died.
The reunions have often been suspended when relations between the two Koreas deteriorate.