Objective: To estimate the prevalence of sex trafficking as a mode of entry into sex work and to examine associations between sex trafficking and HIV vulnerability, recent violence experience, and symptoms of sexual ill health among young female sex workers (FSWs). Methods: A cross-sectional survey of 1137 FSWS aged 18-25 years residing in Andhra Pradesh, India, was conducted. Results: In total, 574 (50.5%) FSWs entered sex work via trafficking. Trafficked FSWs had an increased risk of experiencing sexual violence (adjusted odds ratio [AOR] 2.09; 95% confidence interval [CI], 1.42-3.06) and physical/sexual violence (AOR 1.93; 95% CI, 1.24-3.01), and reporting more clients (AOR 2.25; 95% CI, 1.56-3.22) and more work days per week (AOR 1.48; 95% CI, 1.09-2.02). Symptoms of sexual ill health were not associated with mode of entry into sex work. Conclusion: There is a high prevalence of entry into sex work via trafficking among young FSWs. A history of sex trafficking is associated with greater risk of recent physical and sexual violence and of HIV. Public health interventions must focus attention on young FSWs. (c) 2012 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.