Do I have to file an income tax return in Bulgaria?

It depends on your tax status. Under Art. 4 of the Income Tax Act you count as resident if any one of these applies: a permanent address in the country, more than 183 days of presence in any twelve months, or your centre of vital interests in Bulgaria. A Bulgarian registered address alone does not make you resident while your centre of life stays abroad. Residents are taxed here on worldwide income at a flat ten per cent. To file you need electronic access to the revenue agency, either the free access code or a qualified electronic signature. Collect documents all year, including tax paid abroad, so the double taxation treaty can be applied.