According to exit polls, this result puts Progressive Bulgaria far ahead of former Prime Minister Boyko Borisov's GERB party, which is in second place with 16.2 percent.
Radev, a Eurosceptic and former fighter pilot who opposes military support for Ukraine's war effort against Moscow, stepped down from the presidency in January to run in the election, which came after mass protests in December led to the fall of the previous government.
The eighth elections in the last five years were held in Bulgaria today.
Progressive Bulgaria based its campaign on cracking down on corruption and ending weak, short-lived governments.
However, it appears that he will have to join forces with coalition partners to form a government.
