Fever in a returned traveler from the tropics often poses a diagnostic challenge to the emergency department physician because of the potential for serious morbidity and mortality associated with certain infections such as falciparum malaria and dengue. We report a case of imported dengue fever in a 15-year-old adolescent boy acquired during a recent travel to Guatemala. Dengue fever is a mosquito-transmitted viral infection of global importance. The majority of US residents with dengue become infected during travel to tropical areas. In recent years, dengue has remerged in US tropical and subtropical areas. The disease is underreported in the United States along the Mexican border. The epidemiology, clinical manifestations, diagnosis, control, and prevention of this important global reemerging infectious disease are reviewed. Clinicians should include dengue in the differential diagnosis of febrile illness in children who have recently returned from dengue endemic areas.