Background and objective: Low-level laser therapy (LLLT) is a known modulator of inflammatory process. Herein we studied the effect of 660 nm diode laser on mRNA levels of neutrophils anti-apoptotic factors in lipopolysaccharide (LPS)-induced lung inflammation. Study design/ methodology: Mice were divided into 8 groups (n=7 for each group) and irradiated with energy dosage of 7.5 J/cm2. The Bcl-xL and A1 mRNA levels in neutrophils were evaluated by Real Time- PCR (RT-PCR). The animals were irradiated after exposure time of LPS. Results: LLLT and an inhibitor of NF-κB nuclear translocation (BMS 205820) attenuated the mRNA levels of Bcl-xL and A1 mRNA in lung neutrophils obtained from mice subjected to LPS-induced inflammation. Conclusion: LLLT reduced the levels of anti-apoptotic factors in LPS inflamed mice lung neutrophils by an action mechanism in which the NF-κB seems to be involved.