PURPOSE: Emergency departments (EDs) care for adolescent females with unmet reproductive health care needs. Our objective was, among adolescents presenting to a pediatric ED, to estimate pregnancy risk, describe pregnancy intentions, and identify potentially modifiable factors associated with pregnancy risk. METHODS: Using a paper-based questionnaire, we surveyed females aged 15-19 years presenting to our ED, assessing health care access, sexual behaviors, pregnancy intentions, and receptivity to interventions. We calculated the pregnancy risk index (PRI), which estimates pregnancy risk in the subsequent 12 months, by assessing recent sexual activity, contraception at last intercourse, and known contraceptive failure rates. Independent sample t tests and analysis of variance were used to identify risk factors associated with increased PRI. RESULTS: Of 459 females enrolled, 13% were pregnant and 20% reported prior pregnancy. Among 399 nonpregnant females, 238 (60%) had intercourse in the prior 3 months and 73 (31%) used no contraception at last intercourse. Among nonpregnant adolescents, the PRI was 19.5, which equates to 19.5 expected pregnancies per 100 females per year. Factors associated with higher PRI included lacking a primary provider, prior ED visits, wanting a baby now, and reported partner wantedness of pregnancy. Half believed ED doctors should discuss pregnancy prevention, and one-quarter were interested in starting contraception in the ED. CONCLUSIONS: Nearly one-third of adolescent females in a pediatric ED were either pregnant or could be expected to become pregnant within a year. Screening questions can identify adolescents at high risk of pregnancy in the ED setting. These females should be the target for future pregnancy prevention interventions.