Background: Unintended pregnancy can cause pregnancy termination, which leads to safety risks. The purpose of the study was to analyze the factors that influence unintended pregnancies in Indonesia.Methods: The analysis unit was women aged 15-49 years old who gave birth to the last 5 years. The sample size was 36,472 women. In addition to unintended pregnancy as the dependent variable, other variables analyzed were the place of residence, age, education, husband/partner, employment, wealth, parity, pregnancy termination, the person deciding woman's access to health care, heard about family planning messages on radio, television, and newspaper/magazines. The final stage analysis uses binary logistic regression.Results: Women in urban areas were 1.834 times more likely than women in rural areas to experience an unintended pregnancy. The 20-24 age group was 0.202 times more than the 15-19, while the 45-49 was 1.916 times compared to the 15-19 to experience an unintended pregnancy. Secondary education women were 1.447 times more likely than no education women, while the poorer women were 1.190 times more likely than the poorest women to experience an unintended pregnancy. Parity was found to be a strong determinant of unintended pregnancy. History of pregnancy, decision making by husbandpartner, and heard about family planning messages on radio and television in the last few months are risk factors for unintended pregnancy.Conclusions: Eight variables affect unintended pregnancy, namely age, education, wealth, parity, pregnancy termination, the person deciding woman's access to health care, and heard about family planning messages on radio and television.