In the article – on the basis of published historical sources and research papers – legal regulation of court hearing of land cases in the Ukrainian and Belarusian provinces of the Grand Duchy of Lithuania in the 15th - first part of the 16th century is investigated. This problem has not been much investigated in legal literature. The author aspires to elucidate what kind of courts resolved land disputes as a circuit court, what kind of laws were passed in order to regulate the activity of these courts and how were these laws realized in practice. The author believes that up to the middle of the 16th century there were no per- manent circuit courts for land disputes in the Grand Duchy of Lithuania. All the state courts heard land cases in their permanent quarters and moved in a locality to survey borders only if it was very necessary. The Government of the Grand Duchy of Lithuania stimulated the activity of arbitration and village courts and set them to resolve land disputes in locality. The first permanent circuit court (Sub – Chamber court) for boundary disputes was established in every county during the court reform in 1564-1566.