OBJECTIVE: To examine the association between sexual health and internet use, including social networking websites such as MySpace and Facebook, among a sample of homeless adolescents at high risk of contracting HIV/AIDS. METHODS: In 2009, a survey of internet use among 201 homeless adolescents was carried out. Multivariate logistic regression models assessed how patterns of use were associated with engaging in exchange sex (sex for money, drugs, or housing), recent HIV testing, and online partner-seeking behaviors. RESULTS: Among the surveyed adolescents, 96.5% reported internet use. Most youth accessed the internet at public libraries or youth service agencies. Increased time online and recent engagement in exchange sex were both positively associated with online partner-seeking. Youth connected to family members online were less likely to practice exchange sex and more likely to report a recent HIV test. Youth connected to street-based peers online were more likely to practice exchange sex, whereas youth connected to home-based peers online were more likely to report a recent HIV test. CONCLUSIONS: Although these data are preliminary, homeless youth need more access to the internet, as access facilitates connecting with family and home-based peers whose presence may reduce sexual risk-taking. Access, however, must be carefully monitored to prevent youth soliciting sex online.