Parliamentary elections were held in Poland on 4 March 1928, with Senate elections held a week later on 11 March. The Nonpartisan Bloc for Cooperation with the Government, a coalition of the Sanation faction - won the highest number of seats in the Sejm and 48 out of 111 in the Senate–in both cases, short of a majority. Unlike latter elections during the Sanation era, opposition parties were allowed to campaign with only a few hindrances, and also gained a significant number of seats. The 1928 election is often considered the last fully free election in the Second Polish Republic.

Sanation was a Polish political movement that was created in the interwar period, prior to Józef Piłsudski's May 1926 Coup d'État, and came to power in the wake of that coup. In 1928 its political activists would go on to form the Nonpartisan Bloc for Cooperation with the Government (BBWR).