Treaty of Chudnov, Treaty of Cudnów (Polish: Ugoda cudnowska) or Treaty of Slobodishche (Ukrainian: Слободищенський трактат) was a treaty between the Polish–Lithuanian Commonwealth and the Cossack Hetmanate, signed in Chudniv (Polish: Cudnów) on 17 October 1660 during the Khmelnytsky Uprising. It restored most of the provisions of the Treaty of Hadiach, except for the elevation of Ruthenia to the status equal of the Poland and Lithuania. It invalidated the Pereiaslav Articles, which were often considered unfavorable for Ukraine, severed the union with the Tsardom of Russia and restored Ukraine's state ties with the Polish–Lithuanian Commonwealth. Although the Ukrainian government insisted on the full restoration of the Treaty of Hadiach of 1658, the side of the Polish–Lithuanian Commonwealth, represented by Stanisław Potocki and Jerzy Sebastian Lubomirski, did not agree to the restitution of the Grand Duchy of Ruthenia, leaving other points of the Treaty of Hadiach in force.

The treaty was signed following the Polish victory at the Battle of Chudnov. The treaty meant that the Cossacks withdrew their support from Russia in the Russo–Polish War (1654–67), and transferred it back to the Commonwealth.^[1] The war would eventually be concluded with the 1667 Treaty of Andrusovo.

The Treaty of Chudnov contained the following main points:

• Partition of Ukraine
• Treaty of Hadiach
• Treaty of Pereiaslav
• Truce of Andrusovo