Introduction: Electronic cigarette (e-cigarette) marketing has increased considerably since the product entered the US market in 2007, thereby warranting additional surveillance to monitor recent trends in population-level awareness and utilization. We assessed the prevalence, characteristics, and trends in e-cigarette awareness and use among nationally representative samples of US adults during 2010-2013. Methods: Data came from the 2010-2013 HealthStyles survey, an annual consumer-based web survey of US adults aged >= 18 years. Sample sizes ranged from 2,505 (2010) to 4,170 (2012). Descriptive statistics were used to assess e-cigarette awareness, ever use, and current use (use within the past 30 days) overall and by sex, age, race/ethnicity, education, income, US region, and cigarette smoking status. Trends were assessed using logistic regression. Results: During 2010-2013, increases (p < .05) were observed for e-cigarette awareness (40.9%-79.7%), ever use (3.3%-8.5%), and current use (1.0%-2.6%). Awareness increased among all socio-demographic subpopulations during 2010-2013 (p < .05); an increase in ever use of e-cigarettes occurred among all sociodemographic groups except those aged 18-24 years, Hispanics, and those living in the Midwest (p < .05). During 2010-2013, ever use increased among current (9.8%-36.5%) and former (2.5%-9.6%) cigarette smokers (p < .05), but it remained unchanged among never smokers (1.3%-1.2%). Conclusions: Awareness and use of e-cigarettes increased considerably among US adults during 2010-2013. In 2013, more than one-third of current cigarette smokers reported having ever used e-cigarettes. Given the uncertain public health impact of e-cigarettes, continued surveillance of emerging use patterns is critical for public health planning.