Background: Appropriate infant care practice is crucial for the health and wellbeing of infants. It is the care from delivery until they are one year old, and it includes clean delivery, thermal care, sanitary care, cord care, eye care, breastfeeding, immunization, and identification of newborn risk indications. One of the important reasons for the high level of infant deaths in developing countries is poor household infant care practices. Infant care practice services are not widely used in Ethiopia, especially in Mari Mansa woreda, and it is unclear what factors influence their use. The objective of this study was to assess infant care practice and associated factors among mothers who gave birth within the past six months in Mari Mansa Woreda, Dawuro zone, southern west Ethiopia, in 2023. Methods: A community-based cross-sectional study was conducted using a multi-stage sampling technique among 522 mothers who gave birth in the past six months in Mari Mansa woreda from April 10–25, 2023. Epidata 3.1 was used for data entry and exported to SPSS version 26.0 for analysis. Descriptive statistics such as proportion, frequencies, and measures of central tendency were calculated and presented in tables and figures. Bivariate and multivariable logistic regression analyses were done. In order to declare a statistically significant link, all variables with p-values of less than 0.25 in bivariate analysis and less than 0.05 in multivariate analysis were taken into consideration. Result: 44.4% with 95% CI: (0.40-0.49) of participants had good infant care practices based on seven composite variables. Mothers who can read and write [AOR= 4.49, 95% CI (1.75-11.51)], primary [AOR= 6.52, 95% CI (2.62-16.19)], and college and above [AOR= 14.88, 95% CI (4.19-52.88)]; mothers who had government employers [AOR= 3.07, 95% CI (1.03-9.17)]; mothers who had a high wealth index [AOR= 2.28, 95% CI (1.274.08)]; and mothers who delivered at health facilities [AOR= 4, 95% CI (1.60-10.01)] were significantly associated with infant care practice. Conclusions and Recommendations: In this study, less than half of the respondents had good infant care practices. This indicates infant care practice was unsatisfactory; all responsible bodies were paying attention, taking action, and offering health education about maternal health services, especially at institutional delivery, to assure infant care practice.