Prostki [ˈprɔstki] is a village in Ełk County, Warmian-Masurian Voivodeship, in northern Poland.

It is situated on the Ełk River, in the historic region of Masuria.

[3] The populace was mostly employed in agriculture, while 150 people worked in reloading trains.

[4] 130 Polish citizens were murdered by Nazi Germany in the village during World War II.

[5] The Germans subjected Poles, French and Italians to forced labour in the village.