The Sanation (Polish: Sanacja, pronounced [saˈnat͡sja]) was a Polish political movement created in the interwar period by a cadre of prominent activist from the Nonpartisan Bloc for Cooperation with the Government. Sanacja came to power in the final decade of the Second Polish Republic, as a result of Józef Piłsudski's 1926 May Coup d'État. The movement took its name from his watchword signifying the moral "sanation" (healing) of the Polish body politic. It existed from 1928 until Piłsudski's death in 1935. The Bloc broke up into several factions including "the Castle" ahead of the invasion of Poland by Nazi Germany in 1939.
The Sanation advocates supported authoritarian rule, and rested on a circle of Piłsudski's close associates, including Walery Sławek, Aleksander Prystor, Kazimierz Świtalski, Janusz Jędrzejewicz, Adam Koc, Józef Beck, Tadeusz Hołówko, Bogusław Miedziński and Edward Rydz-Śmigły. It preached the primacy of the national interest in governance, contended against the system of parliamentary democracy.