The emergency department (ED) is an increasingly important site of care for patients who have undergone solid organ transplantation or hematopoietic cell transplantation. It is paramount for emergency physicians to recognize infections early on, obtain appropriate diagnostic testing, initiate empirical antimicrobial therapy, and consider specialty consultation and inpatient admission when caring for these patients. This review provides emergency physicians with an approach to the assessment of transplant patients’ underlying risk for infection, formulation of a broad differential diagnosis, and initial management of transplant infectious disease emergencies in the ED.