Jagiellonia Białystok is a Polish football club based in Białystok that plays in the Ekstraklasa, the top level of Polish football. The club was founded in 1920 by soldiers in the Reserve Battalion in Białystok. Jagiellonia play their home games at Białystok City Stadium.
The club won the Polish Cup and Super Cup in 2010 and qualified to play in the third round qualification of the UEFA Europa League. It was the club's first appearance in the European cup. The club's most successful seasons were the 2016–17 and 2017–18 seasons when they finished 2nd in the Ekstraklasa.
In 2009, the club was involved in a corruption scandal that almost resulted in their relegation to the II liga; however, instead of being relegated the club was deducted 10 points in the following season.
In the 2016-17 season, Jagiellonia Białystok drew an average home league attendance of 12,512.
Białystok City Stadium