Travel related illnesses are a concern among travelers visiting developing countries. These illnesses affect the travelers' plans and the local tourism industry. Few data on travel related illnesses are available from tourist destinations. Foreign travelers answered a self-administered questionnaire on health issues at the departures area of Cuzcos' International Airport between August and November 2002. Self-reported travel related illnesses that occurred during the travelers stay in Cuzco were compared with demographic and risk factors. The total number of participants was 5988. Their mean age was 35.4 years (SD 11.4), and slightly over half were female. The most common countries of residence were the United States (23.5%) and the United Kingdom (20%). The median length of stay in Cuzco was 5 days (IQR: 4-7 days). Pre-travel advice was received by 93.6% of the participants. Half (47.6%) of the participants became ill while in Cuzco. The most common illnesses reported were diarrhea (49.8%), altitude sickness (43.2%), and upper respiratory infections (21.7%). Most participants who reported an illness treated themselves (75.5%), and only 22.1% sought medical attention. It is concluded that a significant burden of disease is observed in travelers to Cuzco. Self-medication is very common and apparently preferred over formal medical attention. © 2008 Elsevier Ltd. All rights reserved.