Purpose: This study examined the effects of photobiomodulation (PBM) associated with endurance running training on oxidative stress (OS) markers in untrained men. Methods: Thirty untrained men distributed into a placebo group (PLA) or PBM group (PBMG) performed 8 weeks of running training, in which the PBMG had the LED application before all training sessions. The PBM was performed by LED application using an equipment with 56 diodes of red light (660 nm) and 48 diodes of infrared light (850 nm) with an energy dose of 60 J on each of the 5 points. The application was done in two regions of the quadriceps muscle, two regions of the biceps femoris, and one region of the gastrocnemius muscle in both legs. The assessments were performed at pre- and post-training, and the OS markers analyzed were malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and oxidized (GSSG). Results: PBM associated with running training did not significantly affect the OS markers CAT, SOD, MDA, GSH, and reduced GSH/GSSG responses after training. GSSG levels decreased in the PBMG and increased in the PLA, with significant difference between the % change values (− 13.5 ± 30.3% vs. 56.3 ± 83.4%; P = 0.043). Conclusions: Therefore, PBM associated with endurance running training did not significantly affect CAT, SOD, MDA, reduced GSH, and reduced GSH/GSSG ratio post-training; however, the GSSG increased in PLA group and decreased in PBMG, indicating a positive effect of the PBM in this marker of OS. [ABSTRACT FROM AUTHOR]