Risky sexual behavior and drug use are factors associated with acquisition of hepatitis B and C. This cross-sectional study investigated hepatitis B and C among 296 adolescents at a sexually transmitted disease clinic in El Paso, Texas, between April 1, 1997, and February 1, 1998. Questionnaires, medical record abstraction, and serum antibody tests provided data on demographics, risk factors, and seroprevalence status. Only 15% of participants always used condoms, 23% had a previous sexually transmitted disease, 46% had more than 1 sexual partner in the last 6 months, and 7% used intravenous drugs. Results showed low seroprevalence of hepatitis B (4.1%) and hepatitis C (3.1%). No significant risk factors were associated with hepatitis B seroprevalence. In contrast, male gender, speaking Spanish, not attending school, having more than 1 sexual partner, and injection drug use were all associated with hepatitis C. Hepatitis B and C seroprevalence rates among high-risk adolescents are lower in El Paso than in other similar US populations, presenting an ideal climate for prevention programs.