Prime minister Rumen Radev voted at the Makgahan Vocational School of Transport in Sofia. He said his vote was for a responsible presidency.
Speaking to reporters after voting, he said the national interest must come first for all institutions.
Radev said that in unpredictable times the country especially needs a president with knowledge, experience, clear positions and principles, who is ready to defend them.
The prime minister said the campaign was built on smear material. He said this put many people off, which is why turnout is low.