BackgroundE-cigarettes have grown in popularity around the world since 2003. Although marketed as a smoking cessation tool, e-cigarettes can lead to tobacco cigarette smoking in youth. In Canada, among all age groups, youth and young adults have the highest prevalence of e-cigarette use. The objective of this study was to assess the factors associated with e-cigarette use among youth and young adults in Canada, and to specifically examine the association between alcohol, marijuana and illicit drug use.MethodsData from the 2017 Canadian Tobacco, Alcohol and Drugs Survey were used. The sample was restricted to those aged 15–24 years (n = 10,322), and main outcome defined as ‘E-cigarette use in the past 30-days’. Multivariable logistic regression was performed to assess the association between the main outcome and substance use variables (illicit drug, marijuana and alcohol use), tobacco exposure variables, and demographic and health-related factors.Results6.2% Canadians aged 15–24 reported using e-cigarettes in the past 30-days, while 23.9% reported having ever tried e-cigarettes. Twenty-three percent of the past 30-day users reported using e-cigarettes every day and 72.5% of the past 30-day users reported having nicotine in their last e-cigarette. Additionally, youth aged 15–17 were 4.95 times more likely to be e-cigarette users as compared to those aged 22–24 (OR: 4.95, 95% CI: 3.1–7.9). Moreover, e-cigarette use was significantly associated with marijuana use (OR:4.17, 95% CI: 2.6–6.7) and alcohol use (OR: 5.08, 95% CI: 2.9–9.0), and approached significance with illicit drug use (OR: 1.68, 95% CI: 1.0–2.9). Furthermore, being a current smoker (OR: 2.93, 95% CI: 1.8–4.7) and male (OR: 2.28, 95% CI: 1.5–3.4) was significantly associated with the outcome.ConclusionThis study is nationally representative and provides insight into e-cigarette use among youth and young adults aged 15–24 years. Given that e-cigarettes can be used as illicit drug delivery systems, more studies are needed to understand how Canadian youth and young adults are using e-cigarettes. Stricter restrictions on public e-cigarette smoking, and awareness campaigns informing youth of risks of e-cigarette smoking should be implemented.