Objectives: Numerous studies and reviews have explored the value of adding therapist support to internet self-help for improving client adherence and outcomes. This study is different as it explores the value of adding internet self-help to face-to-face therapy, from the perspective of practitioners who used both. This study explores practitioners' experiences of whether-and how-internet self-help blended with face-to-face therapy may confer an added value or become an added burden to their routine practice. Methods: Using a structured topic guide, we collected narrative data via 3 focus groups and 1 telephone interview from 11 practitioners across two sites in England. We carried out a thematic analysis within two domains, "value vs. burden". Results: Practitioners reported that internet self-help can confer added value to face-to-face therapy by: fostering client engagement with face-to-face sessions; making therapy ubiquitous beyond sessions; and preventing therapeutic drift between sessions. Conversely, internet self-help can add burden to face-to-face therapy when it is experienced as disruptive, overwhelming and time-consuming. Conclusions: Recognizing and mitigating factors that can turn internet self-help from an added value to an added burden will help practitioners adopt and make the most out of blended therapy.