Travelers are a migratory subgroup of homeless youth who may be especially prone to engaging in risky behavior. This study compared the substance use and sexual behavior of young homeless travelers and non-travelers to evaluate the extent and possible sources of travelers' increased risk. Data came from face-to-face interviews with 419 homeless youth (36.6% female, 34.0% white, 23.9% African American, and 20.0% Hispanic) between the ages of 13 and 24 years (M = 20.1 years, SD = 2.5) who were randomly sampled from 41 shelters, drop-in centers, and street sites in Los Angeles. Travelers were almost twice as likely as non-travelers to exhibit recent heavy drinking, 37% more likely to exhibit recent marijuana use, and five times as likely to have injected drugs. Travelers also had more recent sex partners and were more likely to report having casual or need-based sexual partners and combining sex with substance use. Mediation analyses suggest that travelers' deviant peer associations and disconnection to conventional individuals and institutions may drive their elevated substance use. Differences in sexual risk behaviors are likely attributable to demographic differences between the two groups. Overall, these differences between travelers and non-travelers suggest different service needs and the need for different service approaches. (Contains 7 tables.)