During the past decade, global human movement created a virtually “borderless world”. Consequently, the developed world is facing “forgotten” and now imported infectious diseases. Many infections are observed upon travel and migration, and the clinical spectrum is diverse, ranging from asymptomatic infection to severe septic shock. The severity of infection depends on the etiology and timeliness of diagnosis. While assessing the etiology of severe infection in travelers and migrants, it is important to acquire a detailed clinical history; geography, dates of travel, places visited, type of transportation, lay-overs and intermediate stops, potential exposure to exotic diseases, and activities that were undertaken during travelling and prophylaxis and vaccines either taken or not before travel are all important parameters. Tuberculosis, malaria, pneumonia, visceral leishmaniasis, enteric fever and hemorrhagic fever are the most common etiologies in severely infected travelers and migrants. The management of severe sepsis and septic shock in migrants and returning travelers requires a systematic approach in the evaluation of these patients based on travel history. Early and broad-spectrum therapy is recommended for the management of septic shock comprising broad spectrum antibiotics, source control, fluid therapy and hemodynamic support, corticosteroids, tight glycemic control, and organ support and monitoring. We here review the diagnostic and therapeutic routing of severely ill travelers and migrants, stratified by the nature of the infectious agents most often encountered among them.