By contrast, openly-expressed negative opinions of Putin reached 61% against 48% registered in late February, Alpha Research polling agency said in a statement.
In a new development in public perceptions, a large part of people who continue to like Russia now express disapproval towards Putin himself.
The poll also found that 63% of respondents agreed that Bulgaria belongs in the European Union and NATO, with just 15% supporting potential geopolitical alignment with Russia instead.
"The data show that Bulgarian society is undergoing a period of transformation, which will have an impact not only on its geopolitical attitudes, but also on the support for the individual political forces in the country," Alpha Research commented.
The war in Ukraine is a major focus of attention, with 46% of respondents saying they follow the course of the conflict daily and in detail, whereas 38% are only generally interested.