Background: Electronic cigarettes (ECs) were introduced in South Korea in 2008. ECs are devices that vaporize a solution that the user then inhales unlike combustible cigarettes (CCs) where tobacco leaves are burnt. Therefore, stealth use of ECs could be easier than stealth use of CCs since they produce less odor and smoke. This study aims to examine the use of ECs and factors associated with this trend. Methods: The online panel survey was conducted on 7,000 adults (males 2,300; females 4,700; age, 20-69 years) from November 3, 2018 to November 9, 2018. Females were oversampled given the very low prevalence of tobacco use among women in Korea. Furthermore, multivariate logistic regression analysis was conducted on stealth use of ECs, adjusted for sociodemographic variables and notion for using ECs in indoor public places. Results: In Korea, 83.5% of smokers experienced stealth use of ECs in areas where smoking was prohibited. The online survey shows that users of triple tobacco products including CCs, ECs, and heated tobacco products are more likely to have experienced stealth use than EC single users (OR 2.75, 95% CI 1.48-5.48). In addition, people who answered “Yes” to the question of whether ECs are allowed in the non-smoking area are more likely to have experienced the stealth use of ECs than those who answered “No” or “I don’t know” (OR 2.97, 95% CI 1.69-5.22). Conclusion: Stealth use is common among EC users, especially triple users and those who are not aware of the EC use are also prohibited in indoor public places.

E-cigarette, Stealth use, Smoke-free area, Triple users, Perception