Objective: This study evaluated the effect of low-level laser therapy (LLLT) on postoperative pain in children undergoing primary molar extraction. Materials and methods: This randomized, controlled-crossover, double-blind clinical trial was conducted with 37 children requiring bilateral extraction of primary molars. In one tooth (LLLT group), a GaAlAs diode laser (wavelength, 810 nm; continuous mode, output power 0.3 W; 180 sec, 4 J/cm(2)) was applied intraorally 1 cm from the target tissue immediately following extraction. In the contralateral tooth (control group), the hand piece was applied, but without laser activation. Children and parents rated postoperative pain on the first three evenings following extraction using, respectively, the Wong-Baker FACES((R)) Pain Rating Scale (PRS) and the Visual Analogue Scale (VAS). Parents also reported if their children received analgesics. Data were analyzed using chi(2) and Mann-Whitney U tests. Results: Mean VAS scores were higher for the control group than for the LLLT group on the first and second evenings, and PRS scores were higher for the control group than for the laser group on the first evening, but the differences were not statistically significant (p > 0.05). More analgesics were given to children in the control group on the first evening; however, both groups received equal amounts on the next two evenings (p > 0.05). Conclusions: Within the limitations of this study, LLLT application following primary molar extraction was not found to affect postoperative pain in children.