Background: Adolescent is the transition period from childhood to adulthood. The characteristic of hormonal changes will trigger them for new experience including the use of substance abuse among them. This behavior will impact to high risk of reproductive health related with early sex activity and the number of sex partner and will toward to unwanted pregnancy in different setting of urban and rural areas. Objective: This research will find out more deeply about the risk of the use of substances abuse among youth people to unwanted pregnancy, which is by analyzing of secondary data from Indonesia Young Adult Reproductive Health Survey 2007. Methodology: Case control study is applied in this research and begins from the of unwanted pregnancy among adolescent (110). The matching process conducted after the total case found with age, sex, urban or rural setting (1 case match with 2 controls). The adolescent data of the survey will be linked with data of the mother from DHS 2007 to find the characteristic of mother. Furthermore, the analysis use software of STATA ver 11.2 for different test (x 2 ) among two groups (bivariate) and regressing logistic for risk of substances abuse to unwanted pregnancy (multivariate). Result: The use of substances abuse between case and control is significantly different (p < 0,05) and based on model, the use of alcohol and drug have strong effect to unwanted pregnancy among adolescent. Conclusion and suggestion: Family and policy are needs to be strengthen to protect adolescent from the use of substances abuse as early as possible.