Freiburg scored twice in the opening 14 minutes as new Kaiserslautern coach Krassimir Balakov's reign got off to a losing start.
Karim Guede opened the scoring for Freiburg in the eighth minute and Cedrick Makiadi doubled the lead six minutes later.
Freiburg have now won three and drawn one of their last four games to boost their survival hopes.
In contrast, Kaiserslautern's chances of staying up are looking increasingly slim as the basement boys' winless run grew to 17 matches.
The visitors on Thursday appointed Stuttgart midfielder Balakov as their new coach, replacing the sacked Marco Kurz, but he could scarcely have imagined how poorly his side would start his first game in charge.
Freiburg took the lead ahead after just eight minutes as a poor clearance by Kaiserslautern defender Rodnei hit Freiburg's Sebastian Freis and Guede ran on to the loose ball and struck a left-foot shot into the left corner.
The hosts doubled their advantage when Julian Schuster's corner from the left picked out Makiadi, who planted a header inside the right post.
The visitors struggled to respond and did not have a chance until the 36th minute when Julian Derstroff got behind the Freiburg defence only for goalkeeper Oliver Baumann to make a fine save.
Derstroff had another chance four minutes after the restart, but Baumann again denied him.
Freiburg went close to a third in the 76th minute, but Kaiserslautern keeper Tobias Sippel was able to push away Stefan Reisinger's shot.
Baumann made another save in the 80th minute, this time from Olcay Sahan's 11-yard shot, as Freiburg closed out the game.