The incident occurred early Thursday at Dzhurkovo near the town of Luki, 200 kilometers (125 miles) southeast of Sofia, local mayor Krasimir Manov said.
Details of the accident were not immediately clear, but media reports said the miners were killed in a mine collapse followed by a gas blast.
The two injured miners were taken to a nearby hospital
It was the third mine accident in Bulgaria this year. Four miners died and seven were seriously injured in two separate accidents at a coal mine in the southern part of the country.