ENThe article examines the development of the law of obligations in the Grand Duchy of Lithuania. Its main sources are the Lithuanian Statutes. Other sources are regional charters, the Armenian Statute and customary law. The grounds for the emergence of obligations were transactions, damage, unjust enrichment, the will of the feudal lord, a court decision. The most common way of securing obligations was a pledge. Most of the transactions were made verbally. Transactions worth more than 10 kopecks were carried out in writing. Immovable property transactions were concluded not only in writing, but were also subject to entry into a special register maintained by the courts. The annexes to the 1566 Statute included examples of various transactions. Obligations were terminated by their performance, expiration of the validity period, death of the debtor and the impossibility of performance. Thus, in the Statute of 1588, the law of obligations became an independent institution of civil law. Keywords: Statute; transactions; contract; commitment; causing harm; immovable property.