Background Many dental problems such as tooth decay starts from childhood. In this regard, attitudes and beliefs of mothers about oral-dental health are important. The aim of this study was to determine the factors affecting oral-dental health in children of the mothers who referred to the Qom health centers by using of the Health Belief Model. Materials and Methods This is cross-sectional descriptive analytic study that was performed among mothers who had Children's health dossier in the Qom health centers, Iran. By using of multi-stage sampling and sample size formula, 300 mothers were selected randomly from health assessment centers. Required data from target group were collected by the questionnaire about Health Belief Model in the field of oral health. The data were analyzed using SPSS-20. Results The results showed that there was a positive and significant relationship between the mothers' behavior towards oral-dental health with perceived benefits and self-efficacy (r=0.16,P<0.05, r=0.20, P<0.05, respectively). Also, there was a negative and significant statistically relationship between the mother's behavior towards oral-dental health with perceived barriers (r=-0.15, P<0.05). In addition, there was a positive and significant relationship between mother's behavior toward the oral-dental health and the children's behavior towards this issue (r=0.47, P<0.05). Conclusion The findings is indicator of the importance of the usage of health belief model for assessing of the mothers' perceptions and beliefs about oral-dental health and modeling of their behavior for reinforcing of healthy behaviors in children.