The lists were exchanged in preparation for reunions scheduled for 100 people from both Koreas to take place in September, Yonhap news agency reported Thursday.
The Korea National Red Cross said it sent a list of 250 South Koreans to the North that wished to participate and the North sent a list of 200 names to the South.
Each country will attempt to track down the people on the lists and will whittle down the final combined list to 100 people allowed to attend the reunion at the Mount Kumgang resort on North Korea's east coast Sept. 25-30, Yonhap said.
The first reunion for families separated by the Korean War took place in 1985. After a 15-year hiatus, the reunions resumed and some 18 took place between 2000 and 2010, allowing a total 3,829 families to meet in person.