[2] By-elections were held in the Piotrków Voivodeship on 8 October 1989 to fill a vacancy left by the premature expiration of Grzegorz Białkowski [pl]'s term, who passed away of a heart attack.
[5] By-elections were held in Constituency 36 (Konin) on 16 January 2005 to fill a vacancy left by the premature expiration of Ryszard Sławiński [pl]'s term, who was chosen as a member of the National Broadcasting Council.
[9] In 2010, five by-elections were held, three of which alongside the 2010 Polish presidential election as a result of the passing of Senators Janina Fetlińska, Stanisław Zając and Krystyna Bochenek at the Smolensk air disaster.
By-elections were held in Constituency 21 (Krosno) on 22 June 2008 to fill a vacancy left by the premature expiration of Andrzej Mazurkiewicz's term, as he passed away as a result of a ruptured aneurysm on 21 March 2008.
[11][12] By-elections were held in Constituency 15 (Płock) on 20 June 2010 to fill a vacancy left by the premature expiration of Janina Fetlińska's term, as she passed away at the Smolensk air disaster.
By-elections were held in Constituency 21 (Krosno) on 20 June 2010 to fill a vacancy left by the premature expiration of Stanisław Zając's term, as he passed away at the Smolensk air disaster.
[23] In the lead up to election day, Stokłosa was considered a favorite, accusing the government of being in a conspiracy to deprive him of his wealth, and criticizing mainsteam politicians for "taking advantage" of the Smolensk air disaster.
[29] By-elections were held in Constituency 75 (Tychy) on 8 February 2015 to fill a vacancy left by the premature expiration of Elżbieta Bieńkowska's term, who was chosen as a member of the European Commission.