Objective: Examine trends in e-cigarette use, and Juul use specifically, among U.S. college students. Participants In 2016, we established a cohort of 529 incoming first-year students to a large Midwestern University. In 2018, these students (now third-years) were re-contacted, and a new sample of 611 incoming first-year students was enrolled. Methods: First-year students in 2016 completed a survey assessing their e-cigarette use; in 2018, first- and second-year students reported on e-cigarette use, and use of Juul specifically. Results: From 2016 to 2018, past 30-day e-cigarette use rose from 5.9% to 27.7%. In 2018, for Juul alone, ever use was above 35% and past 30-day use was above 20% for both cohorts. Juul use did not differ by gender, but was associated with higher socioeconomic status (SES) and being White. Conclusions: Findings present disturbing possibilities for long-term nicotine addiction among the next generation, and underscore the need for a rapid public health response.