<b><i>Background:</i></b> Predicting food allergy resolution is essential to minimize the number of restricted foods in children. However, there have been no studies on the natural history of peanut allergy (PA) in Korea. <b><i>Objective:</i></b> This study aimed to evaluate the natural course and prognostic factors of immediate-type PA in children till the age of 10 years. <b><i>Methods:</i></b> We retrospectively collected data of 122 children who developed PA before 60 months of age from 3 tertiary hospitals in Korea. Diagnosis and resolution of PA was defined as an oral food challenge test or a convincing history of symptoms within 2 h after peanut ingestion. The prognostic factors for resolution of PA were identified using the Cox proportional hazard model. <b><i>Results:</i></b> The median (interquartile range) age at diagnosis was 2.0 (1.3–3.0) years. Among the 122 children, PA resolved in 18 (14.8%) children. The level of peanut-specific IgE (sIgE) at diagnosis in the persistence group was significantly higher than that in the resolution group (<i>p</i> = 0.026). The probabilities of resolution of PA were 10.3% and 32.8% at the ages of 6 and 10 years, respectively. A peanut-sIgE level ≥1 kU/L at diagnosis was significantly associated with persistent PA (hazard ratio, 5.99; 95% confidence interval, 1.89–18.87). <b><i>Conclusions:</i></b> Only 10.3% of our patients had a probability of developing spontaneous resolution of PA by 6 years of age. Peanut-sIgE levels ≥1 kU/L at diagnosis were associated with the persistence of PA.