The relationship between conduct problems at age 8 years and teenage pregnancy by the age of 18 years was analyzed in a birth cohort of 491 girls. A statistically significant association was found between early conduct problems and later risk of teenage pregnancy, with girls in the most disturbed 10% of the cohort having a pregnancy rate that was 5.3 times higher (p < .001) than the rate found in the least disturbed 50% of the cohort. The elevated risk of teenage pregnancy amongst girls with early conduct problems was in part, explained by social and family factors that were correlated with early conduct problems, and in part, by a causal chain process in which early conduct problems were associated with increased rates of risk taking behaviors in adolescence, which in turn led to an increased risk of teenage pregnancy. These results suggest that the higher rate of teenage pregnancy among girls with early conduct problems reflected both their relatively disadvantaged family backgrounds and their tendencies to risk taking behavior in adolescence.