"We have taken a decision to cut the number of teams as we're trying to make the championship more attractive," BFU president Borislav Mihaylov told a news conference on Monday.
After the regular season, the top six will form a group which will decide the champions and the bottom eight will form a group to decide the teams who will be relegated.
"We know that countries like Serbia and Croatia also reduced the number of teams in their leagues but then they decided to restore and even increase it to 18," said Mihaylov, who is also a UEFA Executive Committee member.
"But we must try anything to make a stronger league. The leading teams will play 36 games a season and the Top 6 will meet each other four times, which means more interesting matches for the fans."
Mihaylov said four first division teams would be relegated at the end of next season, which starts on Aug. 11 and only two would be promoted from the second division.
The BFU also decided that second division teams should include at least two players under the age of 21 in their starting line-ups from next season.
Many Bulgarian clubs face considerable infrastructure difficulties and are struggling to meet administrative, legal and financial conditions set by UEFA with two teams quitting the second division championship midway through the season.
Last month, Prime Minister Boiko Borisov said the government planned to construct several new stadiums if soccer authorities could attract fans back to the grounds.