Object: Although a rising trend in the incidence of pediatric-onset inflammatory bowel disease (IBD) worldwide, national-level, pediatric population based studies are lacking. In this study, we investigate the epidemiological features of pediatric IBD in Korea, including age and sex-specific incidence and its trends. Methods: We analyzed data of pediatric patients (aged 0–19 years) in the Health Insurance Review and Assessment database, which include information on every patient with IBD diagnosed through uniform criteria based on Rare Intractable Disease registration, from 2008 to 2016. The incidence was calculated per 100,000 population using the resident registration population each year. Annual percentage change (APC) in incidence was determined using Poisson regression analysis. Results: 7,542 incident cases were diagnosed during the study period, 5,113 Crohn\'s disease (CD) and 2,429 ulcerative colitis (UC). Mean annual incidence in Korea for CD was 5.2 per 100,000 and for UC was 2.4 per 100,000. In Poisson regression analysis, incidence of CD increased over the study period significantly (APC: +5.4%, 95% CI 4.3% to +6.5%; p0.001), however APC in incidence of UC did not significantly changed (APC: +0.9%, 95% CI -0.6% to +2.5%; p=0.268). Korean Pediatric IBD patients showed a male predominance in both CD (7.3 vs 2.9 per 100,000, Odds ratio 2.7; p0.001) and UC (2.9 vs 2.0 per 100,000, Odds ratio 1.6; p0.001) Mean annual incidence of CD in Paris classification A1a (aged 0~10 years) was 2.0 per 100,000 and incidence of infantile onset IBD (=2year) was 1.2 per 100,000. Conclusion: Our results suggest that the incidence of pediatric IBD in Korea significantly increased over time, especially in Crohn\'s disease. And the epidemiologic features differ in age and sex-specific population.