Kostomlaty pod Milešovkou (German: Kostenblat) is a municipality and village in Teplice District in the Ústí nad Labem Region of the Czech Republic. It has about 900 inhabitants. Kostomlaty pod Milešovkou lies approximately 10 kilometres (6 mi) south-east of Teplice, 17 km (11 mi) south-west of Ústí nad Labem, and 66 km (41 mi) north-west of Prague.