In 1912 came under the control of the Greek forces as a result of the Ottoman defeat in the First Balkan War.
Muslim Albanians from Florina and the wider region during the population exchange (1923) based on religious criteria were sent to Turkey, and mainly resettled in Bursa.
The town was again in the firing line during World War I, during which it was occupied by Bulgaria, and during the Axis Occupation in World War II, when the town became a centre of Slavic separatism.
For part of the Greek Civil War (1946–1949) the mountains of the Florina area were under communist control.
The Slavic-Macedonian National Liberation Front, later simply the National Liberation Front or NOF, had a significant presence in the area.
By 1946, seven Slav Macedonian partisan units were operating in the Florina area, and NOF had a regional committee based in Florina.
When the NOF merged with the Democratic Army of Greece (DSE), many Slav Macedonians in the region enlisted as volunteers in the DSE.
When the Communists were defeated on February 12, 1949 by the Greek army thousands of communists and Slav Macedonians were evacuated or fled to Yugoslavia and the Eastern Bloc.