Transplant patients are at risk for illnesses and complications days, months, or years after transplantation, and they can present complex challenges for emergency clinicians. This review discusses the general approach to the management of pediatric transplant patients in the emergency department, with a focus on general complications and organ-specific complications after solid organ transplantation. Hematopoietic stem cell transplantation and its common complications will also be discussed. A key step in the management of all transplant patients includes consultation with the patient's transplant team to ensure appropriate testing, treatment, and disposition for these patients.