The Nemzeti Bajnokság I/A (English: National Championship I/A, commonly abbreviated NB I/A) is the highest level league of club men's basketball in Hungary.

At the end of the league stage (14 teams) the top 5 teams play another league stage, another 5 play with each other, and then the top 8 teams qualify for the playoff stage.

The winning team of the final round are the champions of that season.

The two bottom teams play with each other in "Best of three" format.

As we can see from the chart the number of teams in the Hungarian First Division changed a lot and continuously.