The poll by the Institute Allensbach and newspaper Frankfurter Allgemeine Zeitung asked participants who they would vote for if an election were held on Sunday.
The AfD received just 8.5 percent of the theoretical vote - the first time they have dropped below double digits in the Allensbach poll since last July, and the worst level of support since December 2015 when they fell to 8 percent, Focus magazine observed on Wednesday.
Another poll on Wednesday by Forsa research group, RTL and Stern magazine also showed the AfD's support to be waning, with the party receiving just 8 percent support. This was a drop from 12 percent within just four weeks.
"At the moment the AfD can barely gain any points with their strategy to capture voters through the refugee crisis. Furthermore the chaotic administration of US President Donald Trump, which they celebrated at first, is now causing concern given flash points across the world," Forsa researcher Manfred Güllner told Stern.
Since Brexit, Trump's election win, and right-wing populist parties growing in popularity in Europe, German traditional parties have been more concerned about the AfD's rise in regards to the upcoming national election.
Founded in 2013, the AfD failed to gain seats in the German parliament in the federal election that year, but has since grown in support, as its anti-immigrant rhetoric has chimed with discontent over the refugee crisis. Last year it won double-digit percentages of votes in all five state parliament elections, including in Berlin, and nearly a quarter of the votes in Saxony-Anhalt.
Merkel still squeaks ahead in support
The Allensbach poll also showed Chancellor Angela Merkel's conservative Union parties (CDU/CSU) to be at the forefront with 33 percent support. They were followed closely at 30.5 percent by the Social Democrats (SPD), whose chancellor candidate Martin Schulz is hoping to upset Merkel's bid for a fourth term in power.
A poll earlier this month by Bild and Insa research group actually placed the SPD one percentage point ahead of Merkel's Union.
The Stern-RTL poll on Wednesday also showed the SPD just behind the CDU and CSU at 31 percent compared to 34 percent. And this may be because Schulz's bid for the chancellorship is winning the party support from pockets of former AfD supporters.
"The few moderate AfD supporters have emigrated to the SPD because their chancellor candidate Martin Schulz is thought to be capable of displacing Angela Merkel, who they hate so much," Güllner said.
And when the poll asked participants who they would theoretically vote for if they could directly elect a Chancellor (which German voters cannot), Merkel was the preference, but not by much, at 39 percent compared to Schulz's 36 percent.