Purpose: Nurses have been reported to be at an increased risk for miscarriage and preterm labor. However, there is limited knowledge regarding nurses' preconception health behaviors. Therefore, this study aimed to identify factors influencing these behaviors. Methods: One hundred sixty nurses, who were planning their first pregnancy within the upcoming year, participated in an online survey from August 11 to October 31, 2021. Data on preconception health behavior, perceived health status, pregnancy anxiety, nursing practice environment, and social support were analyzed using the t-test, Pearson correlation coefficients, and multiple regression analysis. Results: Age (p=.024), educational level (p=.010), marital status (p=.003), work experience (p=.003), satisfaction with the work department (p<.001), smoking status (p=. 039), and previous health problems related to pregnancy outcomes (p=.004) were significantly associated with nurses' preconception health behaviors. Furthermore, perceived health status (p<.001), pregnancy anxiety (p=.011), nursing practice environment (p=.003), and social support (p<.001) showed significant correlations with preconception health behaviors. Social support (β=. 28, p=.001), satisfaction with the work department (β=.23, p=.032), marital status (β=.22, p=.002), and perceived health status (β=.23, p=.002) were confirmed as factors associated with preconception health behaviors. These factors explained 40.9% of the variance in preconception health behaviors (F=6.64, p<.001). Conclusion: Clinical nurses' preconception health behaviors were influenced by social support, perceived health status, satisfaction with the work department, and marital status. Interventions to improve clinical nurses' preconception health behaviors should target social support and perceived health status. A preconception health behavior education program considering clinical nurses' marital status and satisfaction with the workplace can also be implemented.