The meeting was the first between the rebels and a president of Myanmar since Karen rebels began fighting for self-rule more than 60 years ago, the BBC reported.
Thousands of people have been displaced because of fighting between Karen and government forces.
A spokeswoman for the Karen National Union said the meeting was "warm and pleasant."
The BBC reported that the meeting was part of a major push by the Myanmar government to make deals with separatist groups throughout the country. They have already signed a number of provisional ceasefires with other groups.