Introduction Breast cancer is the most commonly diagnosed cancer in women worldwide, in both high- and low-income countries. Individual and community awareness of breast cancer can be extremely beneficial. However, breast cancer awareness is extremely low among Ethiopian women, particularly in rural areas. Thus, the aim of this study was assessing awareness of breast cancer on reproductive-aged women in West Badewacho Woreda, Hadiya Zone, South Ethiopia, 2020. Method A community-based-cross sectional study was employed from April 18 to May 16, 2020. To obtain data, a pre-tested structured interviewer-administered questionnaire was employed. A multistage random sampling technique was employed to select reproductive-aged women from Woreda. Data was entered into a computer using Epi data version 3.1, and edited, cleaned and analyzed using SPSS windows version 20. Bivariable and multivariable analyses were used to identify determinants related to awareness of breast cancer. Result A total of 578 reproductive-age women participated in this study. Only 364 women of reproductive-age (63%) had heard about breast cancer. 234 (64.3%) of the respondents were aware of breast cancer. After adjusting for other variables, husbands’ educational status [AOR = 0.262; 95% CI (0.076, 0.900)], family history of breast cancer [AOR = 0.281; 95% CI (0.132, 0.594)] and having TV/Radio [AOR = 0.489; 95% CI (0.246, 0.972)] were significant predictors for awareness of breast cancer. Conclusion This study emphasized the importance of raising breast cancer awareness among women in the study area.