OBJECTIVE: To explore experiences during childhood and adolescence that influenced reproductive and sexual health among women who had entered the sex industry in adolescence. METHODS: A qualitative study was conducted using information provided by 25 female sex workers (FSWs) from Tijuana, Mexico, who reported entering the sex industry when younger than 18 years. In-depth, semi-structured interviews were conducted with all participants between January 31, 2011, and July 8, 2011. RESULTS: Four interrelated themes that shaped health experiences-early sexual abuse, early illicit drug use, ongoing violence, and limited access to reproductive and sexual health care-were identified. Participants reporting these experiences were at risk of unintended teenaged pregnancy, spontaneous abortion or stillbirth, and untreated sexually transmitted infections. CONCLUSION: Programs and policies that address social, structural, and individual vulnerabilities during adolescence and adulthood are required to promote reproductive and sexual health among FSWs in Tijuana, Mexico.