Sudden infant death syndrome (SIDS) is the third most frequent cause of infant mortality in the United States (US), which kills 3500 infants a year and accounts for 8% of all infant deaths. The study aims to evaluate mothers' practices of preventing SIDS in Holy Karbala City and to find if there is a relationship between the mothers' practices regarding the prevention of SIDS and demographic variables.Methods: This descriptive study was conducted at primary healthcare centers in Holy Kerbala City, Iraq (PHCCs). A total of 300 mothers answered a specific study questionnaire. The data were collected and analyzed statistically. The study was conducted on women who attend immunization units in PHCCs within the city of Holy Karbala. Both participants and PHCCs were selected randomly. A questionnaire study was constructed by an investigator based on previous studies in addition to the investigator's experiences. The questionnaire included two parts, the first was about mothers' sociodemographic characteristics and the second part reported practices about safe sleep for the child. The SPSS software, version 26 was used to analyze and interpret the data.Results: Mothers had a good level of practice in SIDS prevention with an Mean±SD of 16.6±2.7 and a total score of good practice (14.9±22). There is a significant relationship between mothers' practices concerning their level of education, occupational status, and smoking status (P=0.001). However, there is a non-significant relationship between the mothers' practices and the age, number of children, residency, and socioeconomic status (P>0.05).Discussion: SIDS is the sudden death of an infant under 1 year of age that cannot be explained following a thorough case investigation. This study shed light on the mothers' practices in the prevention of SIDS in holy Kerbala City and found that mothers had a good level of practice in SIDS prevention regardless of their ages, number of children, residency, and socioeconomic status. To raise public awareness of SIDS, a comprehensive health education program should be put in place through mass media and booklets. Additionally, nursing staff must adhere to safe sleep standards, notably the supine posture. They should especially educate new and inexperienced moms about these measures during the antenatal period and after delivery.