Children with cancer are long-term survivors and sequelae from thromboembolic events (TEEs) that include postthrombotic syndrome can cause significant morbidity. Prevalence and risk factors in children with solid tumors are not well described despite some recent studies. If risk factors were better defined, it may be possible to institute appropriate strategies to prevent TEEs and sequelae. A single institution study was performed to investigate the prevalence and risk factors of TEEs in pediatric solid tumors; this included a retrospective analysis of children with central nervous system (CNS) and non-CNS solid tumors with and without TEEs. TEEs were observed in 7.16% of analyzed tumors, higher in the non-CNS (10.6%) than in the CNS tumor category (1.9% P <0.0066). Factors associated with significant risk of TEEs are as follows: presence of a mediastinal mass (P = 0.0005), metastatic disease (P = 0.0086), infection (0.0120), central venous access device (CVAD) (P = 0.0167), and steroids as chemotherapy (P = 0.01). In patients with CVADs, a mediastinal mass (P = 0.0024) and the type of CVAD (peripherally inserted central catheters were more significant risk factors compared with Mediport; P < 0.0001) were significant risk factors. There was a 3.5-fold increased risk of TEEs in patients with CVADs with an underlying diagnosis of lymphoma vs. CNS tumors. Patients with non-CNS solid tumors had increased prevalence of TEEs in our study. Risk factors included metastatic disease, presence of a mediastinal mass, CVAD use, infection, and the use of steroids. Our study underscores the need to conduct a prospective study to formulate the use of prophylactic anticoagulation in patients with identified risk factors to prevent TEEs.