Ostromęczyn [ɔstrɔˈmɛnt͡ʂɨn] is a village in the administrative district of Gmina Platerów, within Łosice County, Masovian Voivodeship, in east-central Poland. It lies approximately 4 kilometres (2 mi) south of Platerów, 10 km (6 mi) north-east of Łosice, and 126 km (78 mi) east of Warsaw.