An anonymous written self-administered questionnaire (in Spanish or English according to the preference of the travelers) collecting demographic information and data on sexual behavior was given to those who volunteered and was collected on the spot.The following variables were included in the questionnaire:sexual orientation, reason for traveling to Cuzco, presence of travel companions (partner, family members, friends, business colleagues),marital status,intention to use condoms,use of illicit drugs,alcohol consumption,history of symptoms suggestive of STD while in Cuzco,number and nature of sexual partners while staying in Cuzco,and places where interaction with local people took place. Two trained interviewers were always available to help the participants in completing the questionnaire