Venous thromboembolism (VTE) in pediatrics is quickly becoming a well-recognized cause of significant morbidity and mortality in children. Most children diagnosed with VTE have a serious underlying primary illness such as cancer, chronic total parenteral nutrition (TPN) dependency, or congenital heart disease. Infants and adolescents are most at risk of developing VTE, and the most significant risk factor is the presence of a central venous line (CVL). The incidence of VTE varies widely with study design and the diagnostic test used to detect thrombosis. Venography remains the gold standard diagnostic test, although ultrasound is increasingly used due to its noninvasive nature, despite concern regarding the sensitivity in upper system VTE. The treatment of uncomplicated VTE in children consists primarily of unfractionated heparin (UFH) initially, followed by oral anticoagulation or low molecular weight heparin (LMWH) for 3 months. LMWH offers many advantages over UFH due to the longer half-life, increased bioavailability, and ease of administration and monitoring in children. Acute complications of VTE in children are numerous and include pulmonary embolism (PE), chylothorax, and superior vena cava syndrome. Long-term morbidity includes recurrent VTE, postthrombotic syndrome, repeat general anesthetics for CVL placement, and eventual destruction of the upper venous system in children with repeat CVL-related VTE. Death from VTE is rare and is primarily due to PE.