Background: The dual use of e-cigarettes and combustible cigarettes poses significant public health concerns due to the compounded risks associated with the use of both products. Understanding the predictors of dual use can inform targeted interventions and tobacco control strategies aimed at reducing nicotine dependence and health risks among adults. Objective: This study aims to identify the sociodemographic predictors of dual use of e-cigarettes and combustible cigarettes among U.S. adults using baseline data from the Population Assessment of Tobacco and Health (PATH) Study. Methods: We analyzed baseline data from the PATH Study, focusing on adult participants who reported the use of both e-cigarettes and combustible cigarettes. Logistic regression models were used to identify the associations between dual use and key sociodemographic variables, including age, gender, race/ethnicity, and education level. Results: The analysis revealed that dual use of e-cigarettes and combustible cigarettes was predominantly observed among young, female, non-Latino, White, and highly educated adults. Younger adults were more likely to engage in dual use compared to older age groups. Females showed higher rates of dual use compared to males. Non-Latino White individuals were more likely to be dual users than individuals from other racial/ethnic backgrounds. Additionally, higher educational attainment was associated with increased dual use, contrary to traditional smoking patterns. Conclusion: The findings highlight specific demographic groups that are at higher risk of dual use of e-cigarettes and combustible cigarettes, particularly younger, highly educated, non-Latino White females. These insights suggest the need for tailored public health interventions that address the unique needs and behaviors of these populations. Future research should explore the underlying motivations and contextual factors contributing to dual use to enhance the effectiveness of tobacco control policies and cessation programs.Full article