Background: Despite of several recent reports on the efficacy of long-pulse pulsed dye laser (LP-PDL) in infantile hemangioma, there still remains a controversy. Objectives: To determine the beneficial effects of early therapeutic intervention with LP-PDL in superficial and mixed hemangioma. Methods: Clinical data of 40 children with 47 hemangiomas in pre-proliferative or proliferative phase who were treated with LP-PDL in a Korean tertiary hospital during the recent five years were analyzed retrospectively. Treatments were repeated at 1- to 4-week intervals until growth stopped. Results: Of the 47 hemangiomas, 32 were superficial and 15 were mixed hemangiomas at presentation. The age at initiation and completion of treatment (mean±SD) was 9.6±5.9 weeks and 18.0±8.6 weeks, respectively, and a positive linear correlation existed between the two. The number of treatments (mean±SD) was 4.6±2.6 per hemangioma, which was lower in superficial than in mixed hemangioma. Improvement in color was documented in 84.4% of superficial and 86.7% of mixed hemangiomas, and 75.0% and 66.7% presented reduction in size, respectively. Hyperpigmentation occurred in two superficial hemangiomas. Conclusion: Early intervention of hemangioma with LP-PDL successfully prevents further growth and accelerates a transition to plateau or involution phase with minimal adverse events, promising a better cosmetic outcome.