(June 1956), uprising of Polish industrial workers that caused a crisis among the Polish Communist leadership as well as in the Soviet bloc and resulted in the establishment of a new Polish regime headed by Władysław Gomułka (Gomułka, Władysław).

After the death of the Soviet leader Joseph Stalin (March 1953), the rigidly authoritarian Communist regime in Poland relaxed some of its policies. It abolished the powerful and tyrannical Ministry of Security, demoting or arresting many of its chief officials, and declared an amnesty for 100,000 political prisoners. These changes stimulated a popular desire for more radical reforms, but the Polish leadership, which included a substantial number of conservative Stalinists, was reluctant. Consequently, the impatient industrial workers of Poznań staged a strike (general strike) on June 28, 1956. Demanding bread and freedom, 30,000 demonstrators marched through the city. Riots soon broke out, the local offices of the secret police and party functionaries were attacked, and a police security officer was lynched. The following day the minister of defense, Konstantin Rokossovsky (Rokossovsky, Konstantin Konstantinovich) (a former Soviet officer), ordered the local military commander to suppress the uprising; and within a few days nearly 60 people were killed, more than 200 were wounded, and order was restored in Poznań.

Although the spontaneous uprising remained localized and could not be sustained, it convinced the Central Committee of the Polish United Workers' Party (PZPR) that significant policy changes had to be undertaken. In the next several months, despite a series of internal party disputes, a visit by Nikita Khrushchev and a Soviet delegation to Warsaw (Oct. 19–20, 1956), and the threat of a Soviet invasion of Poland, the Central Committee elected Gomułka first secretary of the party (Oct. 21, 1956).