For the countries with which Bulgaria has signed bilateral legal assistance agreements and in which there are provisions for exempting documents from Apostille legalisation, the issued documents should bear a stamp of the institution, authorized to do so in the bilateral agreement. In this case the necessary documents need only translation in Bulgarian and certification of the translation by the Bulgarian diplomatic or consular representation in this country. If translation is made in Bulgaria, they should be translated by specialised translation agencies. The signature of the translator should be notary certified in Bulgaria. 

ALBANIA

CUBA

LEBANON

SERBIA

ALGERIA

CYPRUS

LIBYA

SLOVAC REPUBLIC

ARMENIA

CZECH REPUBLIC

MACEDONIA (FYR OF)

SLOVENIA

AUSTRIA

FRANCE

MONGOLIA

SPAIN

AZERBAIJAN

GEORGIA

MONTENEGRO

SYRIA

BELARUS

GREECE

PEOPLE'S REPUBLIC OF KOREA (PRK)

UKRAINE

BOSNA AND HERZEGOVINA

HUNGARY

POLAND

UZBEKISTAN

CHINA

ITALY

ROMANIA

VIETNAM

CROATIA

KUWAIT

RUSSIA

YEMEN

Source: https://www.mfa.bg/bg/uslugi-patuvania/konsulski-uslugi/zaverki-legalizacia/obshta-informatsia