About 250 people have been allowed to travel from the south for three days of meetings at Mount Kumgang resort.
Another group attended reunions earlier this week.
For most of those attending it is the first time that they have had any contact in over 60 years.
Millions of people ended up separated from loved ones by the physical division of the Korean peninsula.
The reunions taking place this week are only the second round in the past five years.
One of those travelling to the resort was the mother of a man who South Korea said was abducted by the North in 1972.
The South Koreans were chosen using a computerised lottery system from among thousands who applied.
Often accompanied by family members, they travelled in a convoy of buses from South Korea to meet their relatives.
Given their age and the infrequent nature of these reunions, they are unlikely to ever see each other again.

Klinger, 36, has hit three centuries in 10 Championship innings so far this season, averaging 94.83.
His side have five Division Two matches left in 2016, but he is likely to miss September's trip to Northamptonshire and the last game, the visit of Sussex.
"We have a baby due in mid-October," the Australian told BBC Radio Bristol.
"Once it gets within that four-week period, I can't be here in case the baby comes. I'd struggle to make it with a 24-hour flight back home if she went into labour. I'll leave on the 11th (of September)."

Dr McBride will combine the temporary role with his current position as chief medical officer.
Among Dr McBride's responsibilities as chief executive will be to improve unscheduled care services and elective care,
He will also lead the development of a new 10-year strategy for the trust.
Announcing the appointment of Dr McBride last month, Health Minister Jim Wells said he was a natural leader and gifted strategist.
"He has been at the forefront of medicine in Northern Ireland for two decades both as an accomplished physician and a highly respected government advisor," he said.
"He possesses all the skills and the wealth of experience required to lead Northern Ireland's largest provider of health and social care services."
The previous chief executive of the trust, Colm Donaghy, resigned in March  of this year to become chief executive of Sussex Partnership NHS Foundation Trust.
In July, Bill Maher, the chief executive of the West/North West Hospitals Group in the Republic of Ireland, was offered the top job in the Belfast Trust but turned it down.
A group of mainly elderly South Koreans have met relatives in the North, in the second of two organised reunions for family members separated by the 1950-53 Korean War.
[NEXT_CONCEPT]
Gloucestershire captain Michael Klinger is set to miss their final two County Championship matches of 2016 as his wife is expecting a baby in October.
[NEXT_CONCEPT]
Dr Michael McBride is beginning work as the new chief executive of Belfast Health Trust on Monday.