ENThe thesis describes the mechanisms related to the functioning of Royal Estates in the Grand Duchy of Lithuania in the second half of the 17th century. Six Lithuanian Estates were established in 1589. Most of them (Šiauliai, Alytus, Grodno, Brest and Kobryn) were located along the western border of the Grand Duchy of Lithuania. The Mogilev Estate was located far to the east, near the border with the Grand Duchy of Moscow. The reconstructed maps of each estate made it possible to determine their area and shape, as well as the location of the capital city. The results of this work showed a significant differentiation of the Lithuanian Royal Estates in that respect criteria. During second half of the 17th century three types of lease contracts for Royal Estates were concluded. The most numerous were agricultural contracts for land used for agricultural purposes. The second type covered forests with their agrarian parts. The third type of contracts – for forest products – concerned the exploitation of timber. The first two types were concluded with nobles of varying wealth, from magnates to petty nobility. The award of this type of contracts was mainly determined by political calculations, but sometimes it was a reward for merit. The third type of contract was a typically commercial obligation, and Polish kings concluded it with merchants, who cut timber and/or produced potash, and then floated them to the ports of Gdansk, Königsberg or Riga.The contracts of the Royal Estates usually lasted three years but were often prolonged. In the second half of the 17th century, the Polish-Lithuanian Commonweaalth suffered from many wars. The Moscow invasion had especially strong influence on the devastation in Lithuanian Estates. Many villages were depopulated and vast area of arable lands became abandoned. All this led to a sharp decline in the royal incomes from Royal Estates (in the Mogilev Estate it was almost 80% lower). In the second half of the analyzed period, a slow recovery from damages and an increase in profitability was noticeable. The events connected with the war accelerated the process of the transition of the royal domain from the farm-serf economy to the rent-based model, which significantly differed from the economic model in the neighbouring private estates. At the end of the 17th century, the farms survived only in the Brest and Kobryn economies, which were combined into one organism at the beginning of the 18th century. Key words: Royal Estates, Šiauliai, Alytus, Grodno, Brest, Kobryn, Mogilev, woodlands, agricultural and forest lease contracts, lessees, war damage, distillery. [From the publication]