Background: Access to contraceptive services and supplies are fundamental to the well-being of women during their reproductive years. Objectives: To determine the prevalence and predictors of modern contraception use among homeless women in Addis Ababa using health belief model. Methods: A cross-sectional mixed methods study used from June 2017- June 2018. A 178 reproductive age group (15-49) homeless women living in Addis Ababa involved in the study. A multi stage sampling technique used to reach individuals. A structured questionnaire mainly with constructs of health belief model and in-depth interview guide used to collect the data. The quantitative data was analyzed using SPSS version 21 statistical software. The data analysis included Univariate, Bivariate analysis and multivariable analysis via logistic regression model with 95% CI and p- value < 0.05. The qualitative data transcribed and analyzed by using a thematic analysis method using the open code software version 3.6. Results: The mean age of respondents was 25 (±6.293) years. All of the respondents had information about Modern contraceptives (MCs). Where the majority 151 (88%) got the information from health professionals. 159 (93%) of the respondents had chance of pregnancy, 140(81.9%) of the respondents, have ever used modern contraceptives and currently, 122 (71.3%) of the respondents were using modern contraceptives and among those currently using more than half, 65 (53.3%) of them were using Norplant. A units increase in score of perceived threat the odds ratio of using MCs increased by 1.044. AOR 1.044 (95%CI 1.015, 1.074) Similarly, a unit increase in sum score of perceived net benefit the odds ratio to the current use of MCs increased by 1.066. AOR 1.066 (95%CI 1.006, 1.129) Limited knowledge of MCs and reproduction, desire to have more children, thinking to be sexually not active and carelessness, fear of being infertile and also no reason was among the reasons for nonuse of MCs while situation of homeless life, life experience and advice from others were the cues to action to use MCs. Conclusion and recommendation: This study concluded that, all of the study respondents have information about MCs and most of them agree on the benefits of MCs. The prevalence of MC use among homeless women in Addis Ababa is good. The high threat perception about negative reproductive health (RH) outcomes and high net perceived benefit of MCs are the major contributing factors for the MC use improvement. MOH and health sectors at different level should develop strategies that can approach and increase the awareness of threats and knowledge about benefits, use and service availability and accessibility of MCs among homeless women.