Ukrainian President Viktor Yushchenko, who took power after Ukraine's Orange Revolution one year ago, opened the forum, which is called the Community of Democratic Choice.
Georgia's President Mikheil Saakashvili -- another leader who took power after large anti-government protests -- is among the initiators of the forum.
The presidents of Latvia, Lithuania, Estonia, Moldova, Slovenia, Macedonia, and Romania are also attending, as well as officials from the Organization for Security and Cooperation in Europe, Bulgaria, and Poland.
Ukrainian officials say representatives of a total of 23 countries are attending the forum, which will focus on regional stability, the development of democracy, and economic cooperation.
Russian President Vladimir Putin was invited, but is reportedly sending an embassy official in his place.