Purpose: Use of electronic cigarettes ("e-cigarettes" is rapidly rising, and is especially prevalent among young adults. A better understanding of e-cigarette perceptions and motivations for use is needed to inform health communication and educational efforts. This study aims to explore these aspects of use with a focus on comparing young adults to older adults. Methods: In this qualitative study, the investigator conducted semi-structured interviews among a purposive sample of e-cigarette users. Thematic content analysis was used to analyze qualitative data and document themes. Results: e-cigarettes were most commonly used for smoking cessation among both age groups. Young adults described other motivations for use including doing smoke tricks, being able to consume a wide variety of flavors, and helping them study. Some interviewees (11%) believed e-cigarettes were a healthy alternative to conventional cigarettes, while many other users (30%) expressed concerns about the unknown risks of e-cigarettes. Conclusion: Findings were generally consistent across both age groups in their perceptions of harm from e-cigarettes and in subjective effects such as perceived addictiveness. However, individuals under 30 described unique motivations for e-cigarette use. Health messaging targeted to young adults should emphasize the potential health risks of e-cigarette use and recognize their distinct motivational aspects.