Objectives The purpose of this prospective study was to evaluate a possible clinical benefit of LLLT in endodontic surgery. Study design Seventy-two endosurgery cases on incisors and premolars were included to the study and were split randomly into an LLLT test group, a placebo group, and a control group. In the LLLT group, irradiation was performed intraoperatively and postoperatively 1, 3, and 7 days after surgery. In the placebo group, irradiation was performed without laser activation. In the control group, neither LLLT nor placebo therapy was used. Swelling, wound healing, and pain were evaluated by a blinded investigator 1, 3, and 7 days postoperatively. Results No statistically relevant differences between the LLLT and the placebo groups were found. Patients in the control group reported on statistically relevant stronger pain. Conclusion In routine endodontic surgery cases, LLLT does not achieve a significant clinical benefit. Further, the results indicate a prominent placebo effect of the soft laser therapy.