Background: Internet and short message service are emerging tools for chronic disease management in adolescents, but few data exist on the barriers to and benefits of internet-based asthma self-management. Our objective was to reveal the barriers and benefits perceived by adolescents with well-controlled and poorly controlled asthma to current and internet-based asthma management. Methods: Ninety-seven adolescents with mild-to-moderate persistent asthma monitored their asthma control on a designated Web site. After 4 weeks, 35 adolescents participated in eight focus groups. Participants were stratified in terms of age, gender, and asthma control level. We used qualitative and quantitative methods to analyze the written focus group transcripts. Results: Limited self-efficacy to control asthma was a significant barrier to current asthma management in adolescents with poor asthma control (65%) compared to adolescents with good asthma control (17%; p < 0.01). The former group revealed the following several benefits from internet-based asthma self-management: feasible electronic monitoring; easily accessible information; e-mail communication; and use of an electronic action plan. Personal benefits included the ability to react to change and to optimize asthma control. Patients with poor asthma control were able and ready to incorporate internet-based asthma self-management for a long period of time (65%), whereas patients with good control were not (11%; p < 0.01). Conclusions: Our findings reveal a need for the support of self-management in adolescents with poorly controlled asthma that can be met by the application of novel information and communication technologies. Internet-based self-management should therefore target adolescents with poor asthma control.