OBJECTIVES:This study investigated the prevalence and correlates of electronic cigarettes (e-cigarettes) use in Taiwan. DESIGN AND SETTING:We studied a nationally representative random sample in the 2015 Taiwan Adult Smoking Behavior Survey. PARTICIPANTS:This study included 26 021 participants aged 15 years or older (51% women, 79% non-smokers, 16% aged 15-24 years), after excluding 31 persons (0.1%) who had missing information on e-cigarette use. PRIMARY OUTCOME MEASURES:The prevalence of ever having used e-cigarettes was calculated in the overall sample and by smoking status (current, former and never) or age (15-24, 25-44 and ≥45 years). We performed multivariable log-binomial regression to assess correlates of ever having used e-cigarettes among all participants and separately for subgroups by smoking status and age. RESULTS:Approximately 3% of all participants had ever used e-cigarettes. The prevalence of ever having used e-cigarettes was high in current smokers (14%) and people aged 18-24 years (7%). E-cigarette use was particularly common in people aged 15-24 years who were current (49-52%) or former (22-39%) smokers. Ever having used e-cigarettes was positively associated with tobacco smoking (adjusted prevalence ratio (aPR): 21.5, 95% CI 15.4 to 29.8, current smokers; aPR: 8.3, 95% CI 15.2 to 13.1, former smokers), younger age and high socioeconomic status. Age remained a significant factor of ever having used e-cigarettes across smoking status groups. Among non-smokers, men had a 2.4-fold (95% CI 1.5 to 3.8) greater prevalence of e-cigarette use than women. CONCLUSIONS:E-cigarette use was uncommon in the general population in Taiwan, but prevalence was high among smokers and young people. This study highlights challenges that e-cigarettes pose to tobacco control, which warrant high priority action by policymakers and public health professionals. E-cigarette regulations should focus on young people.