A team of Red Cross officials from the South went to the North for the talks
Red Cross officials from North and South Korea have begun talks aimed at allowing families divided by the border to begin meeting again.
The reunions have been suspended for almost two years because of worsening ties between the two nations.
This new round of negotiations reflects a recent improvement in relations between the two sides, and reunions could now resume as early as October.
About 100,000 families were separated by the 1950-53 Korean War.
The BBC's John Sudworth in Seoul says that for hundreds of thousands of them, time is running out.
The North and South are still technically at war, as a peace treaty was never concluded at the end of the inter-Korean conflict.
There are still no exchanges by post, telephone or e-mail between people living across the heavily fortified border.
The three-day official talks are being held in the North Korean resort of Diamond Mountain (Mount Kumgang).
Thousands of families were separated by the 1950-53 war
"Since it is a meeting being held after a year and nine months, the main topic is the dispersed family issue," chief South Korean delegate Kim Young-chol said.
Even if talks are successful, it is likely that only a fraction of those families on the waiting list will be able to see their relatives in the highly emotional but all-too-brief meetings, our correspondent says. Only about 100 families are likely to be involved.
In the early part of the decade, the two countries regularly held Red Cross talks to discuss family reunions and other humanitarian issues. About 16,000 families were briefly reunited.
However the reunions were stopped after South Korean President Lee Myung-bak took office in February 2008, amid North Korean anger at his policy of ending unconditional aid handouts.
He has tied a resumption of aid to progress on North Korean nuclear disarmament.
Earlier this year, relations between North Korea and the rest of the world were extremely strained. It was heavily criticised in May for conducting its second nuclear test and a series of ballistic missile launches.
But the agreement to hold the Red Cross talks is just one of a series of conciliatory gestures by North Korea in recent weeks.
Last week, Northern officials attended the funeral of South Korea's former President Kim Dae-jung.
Former US President Bill Clinton also visited the North recently, and secured the release of two American journalists detained there.
North Korea also announced this month that it would ease restrictions on cross-border traffic imposed last year amid the rising tension.