Introduction: Syphilis is a sexually transmitted infection caused by the Bacterium Treponema pallidum, and continues to be a major public health problem worldwide. It can spread through various means such as unprotected sex, mother-to-fetus, and blood transfusion. Mother-to-child transmission of syphilis during pregnancy can result in adverse pregnancy outcomes, such as early fetal death, stillbirth, premature birth, and low birth weight Despite widely available and affordable screening methods and treatment, syphilis infection is a public health problem in pregnant women in sub-Saharan Africa. This study aimed to assess the magnitude of syphilis and its associated factors among pregnant women attending antenatal care at public health facilities in Hawassa Zuria Woreda, Sidama, Ethiopia. Methods: A facility-based cross-sectional study was conducted in Hawassa Zuria public health facilities from November 1-30, 2024. A total of 482 participants were selected using systematic sampling methods. Data were collected through structured interviews using a pre-tested questionnaire and by reviewing the records. Epi-data version 4.4 was used to code and enter the data, and SPSS version 26 was used for analysis. Bivariable logistic regression was employed to identify candidate variables for multivariable logistic regression with a significance level of ? 0.25. A multivariate logistic regression model was used to investigate factors associated with syphilis infection, and a p-value of <0.05 was considered statistically significant. Results: The magnitude of syphilis among pregnant women attending antenatal care clinics was 3.8% (95% CI: 3.61-3.99). Having multiple sexual partners (AOR = 3.68; 95% CI: 1.22 - 11.11), alcohol use (AOR = 7.34; 95% CI: 2.31 - 23.36), and HIV positive women (AOR = 10.22; 95% CI: 2.03 - 51.53) were significantly associated with syphilis infection. Conclusion and Recommendation: The magnitude of syphilis was high. Having multiple sexual partners, being HIV-positive, and alcohol consumption were factors significantly associated with syphilis infection. Therefore, substantial efforts have to be made to provide regular health education for pregnant women at antenatal clinics to avoid risky sexual behaviors, raise awareness on the transmission and prevention mechanisms of syphilis, promote safe sexual practices, and strengthen partner testing and treatment.