In the middle of the 17th century the decanate of Słonim was one of the 26 decanates in the Diocese of Wilno. According to the synodal acts of 1669 the decanate was divided into 14 parishes. They were Darewo, Dworzec, Horodyszcze, Jelna, Lachowicze, Motczadź, Mysz, Polonka, Rohotna, Słonim, Stwołowicze, Wsielub, Zadźwieja, and Zdzięcioł. Most of the churches in the Słonim decanate were built of wood, just as in the rest of the Wilno diocese. The church, surrounded by the churchyard, had usually a separate bell tower; sometimes there was yet another building in the compound, the mortuary. There were only three churches made of stone in the whole decanate.This article is concerned with the damage done to the Roman Catholic parish churches of the Słonim decanate during the Russian War of 1654-1667. The Muscovite army under A. M. Trubetski entered the Słonim decanate in September 1655. Another wave of devastation resulted from the resumption of hostilities in 1659. In the autumn of that year a Russian army commanded by Kniaz Khovanski began to roam in the Grand Duchy of Lithuania. In March 1660 Khovanski directed his troops against the Lachowicka Fortress. While fierce fighting around the beleaguered fortress continued for months, the Russians devastated the whole neighbourhood, i.e. villages which were part of the Słonim decanate. A lot of information about the churches in the region is provided by records of visitations in the Słonim decanate from the year 1653-54 and 1668. For ten parishes there are also visitation protocols from the year 1633. Another relevant source is a set of 5 church inventories from the period 1662-1675. A very important source of information about the effect of recent hostilities on local churches is a record of visitations carried out by Mikołaj Słupski, suffragan of Belorus, in 1673—1677. The time scale of the extant visitation material allows us to assess the condition of the churches beforeand after the war. Actually, the fullest extant documentation of visitations and inventory files concerns the decanate of Słonim. The analyses of inventory lists special attention was paid to changes in the churches’ most valuable possessions such as silver chalices, pyxes, monstrances, reliquaries, ampullae, liturgical vestments and various furnishings. Students of the Grand Duchy of Lithuania agree that the Russian War of 1654-1667 is — alongside the christening of Lithuania and the Partitions — one the major turning points in the history of the region.