Final opinion polls indicate that the result will be very close, and if the anti-smoking lobby proves successful, it could be a forerunner to a general ban on smoking in restaurants and bars in the whole of Germany.
Since it was decided that the smoking ban came under the jurisdiction of individual states, Germany has taken a piecemeal approach to a ban that is already in effect in much of Europe. Different states have different regulations, with exceptions made for various types of bar, but no state has imposed an absolute ban.
Bavarian state premier Horst Seehofer said he hoped that Sunday's plebiscite would conclude a debate that has wracked the state for nearly five years. The vote "will have a pacifying effect on society," he said. "And then we'll have some peace!"
If the pro-smoking faction wins, then Bavaria's existing law will remain in place, which allows smoking in beer-tents, one-room bars and designated rooms.
Seehofer himself has remained neutral throughout the campaign. According to a report in news magazine Der Spiegel, this is because his party, the Christian Social Union (CSU), has "had its fingers burnt" taking sides on the issue in the past. Bavaria's ruling party lost its absolute majority in the 2008 state parliament elections, partly because it backed a cross-party total smoking ban in December 2007.
Forced into a coalition with the neo-liberal Free Democratic Party (FDP), Seehofer subsequently loosened the ban and allowed certain exceptions.
This resulted in a massive anti-smoking campaign in Bavaria, which collected 1.3 million signatures and thus triggered Sunday's referendum. If the anti-smoking campaign is successful, the total ban would automatically come into effect on August 1, though there would be an amnesty for this year's Oktoberfest.