Rząśnik-Majdan (Polish pronunciation: [ˈʐɔ̃ɕɲik ˈmajdan]) is a village in the administrative district of Gmina Wąsewo, within Ostrów Mazowiecka County, Masovian Voivodeship, in east-central Poland. It lies approximately 13 kilometres (8 mi) west of Ostrów Mazowiecka and 85 km (53 mi) north-east of Warsaw.