Objectives: To determine the immediate pain relief effect of low-level laser therapy on sports injuries in athletes and degree of pain relief by the therapy. Design: Double-blind, randomized, comparative clinical study. Methods: Participants were 32 college athletes with motion pain at a defined site. Participants were randomized into two groups in which the tested or placebo laser therapy was administered to determine pain intensity from painful action before and after laser irradiation, using the Modified Numerical Rating Scale. The post-therapeutic Modified Numerical Rating Scale score was subtracted from the pre-therapeutic Modified Numerical Rating Scale score to determine pain intensity difference, and the rate of pain intensity difference to pre-therapeutic Modified Numerical Rating Scale was calculated as pain relief rate. Results: Low-level laser therapy was effective in 75% of the laser group, whereas it was not effective in the placebo group, indicating a significant difference in favor of the laser group (p < 0.001). Pain relief rate was significantly higher in the laser group than in the placebo group (36.94% vs. 8.20%, respectively, p <0.001), with the difference in pain relief rate being 28.74%. Conclusions: Low-level laser therapy provided an immediate pain relief effect, reducing pain by 28.74%. It was effective for pain relief in 75% of participants. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.