Background. Heterosexual transmission within serodiscordant relationships is the core source of new HIV infections. Although consistent condom use can significantly reduce HIV transmission risk among serodiscordant couples, it has not been extensively studied in Ethiopia. Consequently, the current study looked at the proportion of serodiscordant couples in Ethiopia who used condoms consistently and the factors associated with that. Methods. A cross-sectional was conducted from October 2019 to June 2020. For the quantitative findings to be more robust and reliable, a qualitative design was incorporated. An interviewer-administered questionnaire was used to collect the data. Qualitative data were collected using gender-matched four focus group discussions. Multivariable logistic regression was conducted to identify factors associated with consistent condom use. The statistical significance of the variables was declared at a
P
value of less than 0.05. Results. This study confirmed that the proportion of consistent condom use was 58.4% [95% CI: 53.1-63.1%]. After controlling for all other variables, unmarried partners,
adjusted
odds
ratio
AOR
=
0.44
[95% CI: 0.229-0.877] and students and employees,
AOR
=
0.33
[95% CI: 0.130-0.846] and
AOR
=
0.39
[95% CI: 0.165-0.939], respectively, were less likely consistently use condoms, whereas couples living together,
AOR
=
1.86
[95% CI: 1.197-2.195], receiving counseling about condom use,
AOR
=
1.90
[95% CI: 1.182-3.076], and having more knowledge about HIV,
AOR
=
1.61
[95% CI: 1.031-2.525] were more likely to use condoms consistently. Conclusion. Despite its importance, the proportion of consistent condom use among serodiscordant couples was significantly low. To improve condom use consistently, planners, policymakers, and health care practitioners should consider the factors listed above when making decisions. There should be an increased focus on student and employee intervention as well.