Crohn's disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel disease (IBD) are idiopathic, life-long, destructive chronic inflammatory conditions of the gastrointestinal tract that typically manifest during late childhood and adolescence. These chronic relapsing diseases may have devastating effects on patients. New medical progress in IBD includes genetics, gut ecology and microflora, immune mechanisms, and targeted biologic therapies. This article reviews the current understanding of the etiopathogenesis of IBD, the emerging epidemiologic data in pediatric IBD, clinical presentations, diagnostic evaluation, distinctions between adult and pediatric-onset disease, and a comprehensive review of both conventional and new therapies, highlighting age-specific issues such as growth, sexual delay, and psychological and behavioral health.