Background: The use of condoms is as a part of prevention against the risk of unwanted pregnancy and sexual transmitted diseases. Indonesia Demographic and Health Survey of Adolescent Reproductive Health in 2012 showed an increase in condoms use at the first sexual intercourse by unmarried adolescents in five years before survey. This study was to determine the most variables which influencing on condoms use at the first time by unmarried adolescents. Methods: This study used a cross sectional design and secondary data from Indonesia Demographic and Health Survey of Adolescents Reproductive Health in 2012. Population were unmarried adolescents aged 15-24 years old and samples were unmarried adolescents who ever had sexual intercourse and answer questions completely. Data analysis was done using univariate, bivariate and multivariate. Results: Condoms use at the first sexual intercourse by unmarried adolescents in Indonesia about 24.7%. The results of bivariate analysis indicate that there is a significant relationship between economic status (p-value = 0.007), information access (p-value = 0.042) and knowledge (p-value = 0.009) with the condoms use at the first sexual intercourse by unmarried adolescents in Indonesia. Economic status is the most influences factor of condoms use at the first sexual intercourse by unmarried adolescents (RP = 1.629 95% CI: 1.076 to 2.468; p-value = 0.021). Conclusion: These results can be informed not only on prevention and control program of HIV/AIDS but also on sexual transmitted infections in Indonesia which adolescents as the target. Keywords: Adolescents, Condom, First, Intercourse, Sexual DOI: https://doi.org/10.26553/jikm.2016.8.2.91-99