Background: Drug abuse constitutes a major sociomedical problem throughout the world. A unique subgroup with a higher potential of drug abuse are young travelers to Southeast Asia. Less than a handful of studies have focused on this population, and even fewer have been carried out on site. Our aim was to characterize the phenomenon of drug abuse among Israelis and other nationals, and to define risk factors that would predict which travelers are prone to abusing drugs. Methods: Data was collected through questionnaires that were distributed in Southeast Asia to 430 travelers. Medical students administered the questionnaires across India,Thailand, Nepal, Vietnam, and Laos during 2002 and 2003. Results: Questionnaires from 231 Israelis and 199 other nationals (mostly from the United Kingdom, Sweden, Australia, and Germany) were analyzed. These travelers had a mean age of 25.3 years. We found that 54.3% of the travelers abused drugs during the trip. Israelis (66.2%) abused drugs more frequently than did non-Israelis (40.7%, p < .001 ). Males abused drugs significantly more than females did, as did secular more than religious people; however, those with an academic degree abused drugs less than others. For 23.5% of the Israelis, the trip was their first encounter with drugs. Of the entire cohort, 72% abused cannabis products, and most of them (49.6%) did it on daily basis. The use of "hard" drugs (eg, lysergic acid diethylamide) was more common among non-Israelis than among the Israelis (37% and 20%, respectively; p < .006). Much higher rates of drug abuse (70.1%) were found in India than in other Southeast Asian countries. Logistic regression identified that prior use of drugs, Israeli nationality, travel to India, cigarette smoking, and traveling alone were significant predictors of drug abuse. Conclusions: There is a disturbingly high rate of drug abuse in travelers to certain Southeast Asian countries, both among Israeli and other nationals. For many youngsters, this is their first encounter with drugs, and many plan to continue abusing drugs upon their repatriation. Travelers to Southeast Asia should be a major target group for primary, preventive, antidrug campaigns worldwide.