Introduction: We aimed to compare the effectiveness of 15- and 30-W holmium: yttrium-aluminum-garnet (Ho:YAG) laser devices used in the treatment of pediatric kidney stones.Methods: Eighty-six consecutive pediatric patients who underwent retrograde intrarenal surgery (RIRS) between February 2010 and August 2020 were enrolled in the study. After exclusion criteria were applied, the data of 79 children were evaluated retrospectively. Patients were divided into two groups according to the laser device power of 15 W (Group 15: N = 30) and 30 W (Group 30: N = 49). The groups were compared according to demographic characteristics, stone feature, and clinical efficacy.Results: The age, gender, height, weight, and stone characteristics were similar between the groups. The mean operation time was shorter in Group 30. The stone-free rate after the first RIRS session (SF1) was 66.7% in Group 15 and 83.3% in Group 30. The SF1 for 20-mm or larger kidney stones was found to be 0% in Group 15 and 62.5% in Group 30. However, there was no statistically significant difference between the two groups in terms of stone-free rate.Conclusions: In pediatric kidney stone treatment, 30-W Ho:YAG laser devices should be preferred as they shorten the operation time compared with 15-W devices and provide the final stone-free status with fewer procedures, especially in large kidney stones.