The four are members of the regional group GUAM.
The summit is reportedly aimed at reducing Moscow's influence over energy supplies and peacekeeping operations in the region.
The presidents of Georgia, Ukraine, and Azerbaijan -- Mikheil Saakashvili, Viktor Yushchenko, and Ilham Aliyev -- will participate in the gathering.
Moldova's president, Vladimir Voronin, is not attending, but Prime Minister Vasile Tarlev is taking his place.
The leaders will be joined by the presidents of Lithuania, Poland, and Romania.
(AFP, Civil Georgia)