Background: Idiopathic guttate hypomelanosis (IGH) is common acquired leukoderma characterized by discrete, tiny, white macules in the elderly. Until now, there was no definite therapeutic modality for IGH. Objectives: To investigate the effectiveness of low-fluence fractional CO₂ laser in the treatment of IGH Methods: A retrospective review was performed, and a total of 87 lesions on 26 body parts in 17 patients with IGH were included from October, 2016 to June, 2017. A CO₂ fractional laser treatment was performed on all lesions with 2 passes of 2-4 mJ, 400 spots/cm2 with no anesthesia at a 1-week interval. All lesions were classified into three body parts including face, chest, and extremities, and were evaluated according to the body parts. Clinical assessments were evaluated using 6-point scales (0, no; 1, mild; 2, moderate; 3, good; 4, excellent; 5, complete response). Results: Overall, 61.5% (21 out of 26 body parts) showed excellent or complete response after a median of 5.5 treatment sessions (range: 2-9). In the subgroup analysis, 80% (8/10) of face lesions showed excellent response, while 40% (4/10) of extremities reached excellent response. Transient erythema and crust after treatment was common, and one patient stopped treatment because of prolonged hyperpigmentation at irradiation site. Conclusion: Low-fluence fractional CO₂ laser therapy could be an effective option for IGH. It is convenient without need for anesthesia.