Background & aim: Childbirth preparation has been globally supported as an important part of safe maternity program. Birth preparedness and complication readiness (BP and CR) aimed to reduce delays in seeking care, arrival, and care during childbirth and immediate postpartum period. The aim of this study was to assess the knowledge and practice of BP and CR, as well as its associated factors, among antenatal care attendants in Bule Hora town in the Oromia region in Ethiopia. Methods: This facility-based cross-sectional study was conducted within February to June 2019. A total of 272 women were selected using systematic sampling and interviewed by previously tested structured questionnaires. Data analyzed using Epi Info (version 6.4) and SPSS software (version 25) with binary logistic regression and multiple logistic regression analyses. Results: Out of 272 mothers, 46.3% practiced four or more BP and CR steps. Attendance in secondary school (OR=2.42; 95% CI: 1.73-5.48) and college or university (OR=4.12; 95% CI: 1.61-7.87), maternal occupation (OR=4.12; 95% CI: 2.64-9.69), having 1-3 (OR=1.49; 95% CI: 1.08-6.96) and higher than or equal to 4 prenatal visits (OR=3.54; 95% CI: 1.72-9.03), knowledge of main warning signs during pregnancy (OR=6.68, 95% CI: 4.80-11.77) and also during labor and childbirth (OR=4.54; 95% CI: 2.20-10.28), were independent predictors associated with BP and CR practice. Conclusion: The level of BP and CR among women in the study area was low. In general, policymakers and planners should improve BP and CR in women and provide pregnant women, their families, and communities with associated information.