BackgroundAbortion is one of the leading causes of maternal death in low- and middle-income countries. In Nepal, abortion is reported to be the third leading cause of maternal death. We aimed to investigate the prevalence and factors associated with abortion and unsafe abortion in Nepal.MethodsThis study is based on a nationally representative sample of the Nepal Demographic and Health Survey 2011. Women who had ever had a terminated pregnancy (n = 2395) were studied. The survey elicited information on the most recent abortion. Unsafe abortion was defined according to the providers of abortion services. Binary logistic regression was used to calculate odds ratios (ORs) and 95% Confidence Intervals (CIs) of abortions and unsafe abortions due to demographic, socio-economic and lifestyle-related characteristics. The interaction of the reason for abortion with age and educational status in predicting unsafe abortion was calculated using the predictive margins and their 95% CI.ResultsThe five-year prevalence of abortion was 21.1% among women of reproductive age who ever had a terminated pregnancy and 16.0% of total abortions were unsafe. Women of Buddhist religion (OR 2.15; 95% CI 1.04, 4.44), those who were literate (secondary level education OR 1.69; 95% CI 1.22, 2.34), those who knew about legal abortion (OR 1.88; 95% CI 1.41, 2.52) and those who were aware of safe places for abortion services (OR 4.96; 95% CI 3.04, 8.09) were more likely to undergo an abortion. Likewise, women in age group 25–34 years (OR 0.43; 95% CI 0.19, 0.97) and those who were in the richest wealth quintile (OR 0.10; 95% CI 0.04, 0.25) were less likely to undergo an unsafe abortion. Educated women of 25–34 years reporting “health risk” as the reason for abortion had a decidedly lower probability (< 10.0%) than the others of going through the unsafe abortion.ConclusionsThe prevalence of abortion in Nepal remains high. Education, religion, age, knowledge about legal abortion and safe places to undergo abortion were the major decisive factors associated with abortion. Young, poorest and uneducated women were more likely to undergo unsafe abortions. Therefore, intervention studies among these target groups are warranted.