To identify social and behavioral factors associated with unintended pregnancy among adolescents in Russia. Cross-sectional. The investigation group consisted of 145 adolescents aged 15-19 years admitted to a youth-friendly clinic for induced abortion. The control group consisted of 77 sexually active never pregnant adolescent girls of similar age admitted for other reasons. Both groups completed a self-administered questionnaire about their occupation, educational level of their mother, family structure and socioeconomic status, relationship with their mother, sexual behavior, and substance use. Factors associated with unintended pregnancy. In the bivariate analysis pregnant adolescents tended to have a lower educational level, to live in a nonintact family, to prefer stronger alcohol drinks, and to have a younger age at sexual debut and more frequent sexual intercourse. In the log-linear model six factors appeared to be directly linked to pregnancy: mother's lower education, alcohol consumption, nonintact family structure, low academic grades, higher frequency of sexual intercourse, and lower age at sexual debut. Although the issue of unwanted pregnancy and possible ways to prevent it should be kept in mind in the psychosocial assessment of any adolescent, the results of our study suggest that some adolescents are at increased risk of unwanted pregnancy. This group includes adolescent girls with low educational attainment, living in a disrupted family, and reporting other risk behaviors. These adolescents might specially benefit from specific preventive programs to reduce the number of adverse outcomes.