ObjectiveTo investigate the cost-utility of the internet-based intervention Featback provided with different levels of therapist support, in comparison to a waiting list. MethodThis economic evaluation was conducted from a societal perspective and was part of a randomized controlled trial in which participants (N=354) with self-reported ED symptoms were randomized to: (1) 8 weeks of Featback, consisting of psychoeducation and a fully automated monitoring- and feedback system, (2) Featback with low-intensity (weekly) therapist support, (3) Featback with high-intensity (three times a week) therapist support, and (4) a waiting list. Participants were assessed at baseline, postintervention, and 3-month follow-up. Cost-utility acceptability curves were constructed. ResultsNo significant differences between the study conditions were found regarding quality-adjusted life-years (P=0.55) and societal costs (P=0.45), although the mean costs per participant were lowest in the Featback condition with low-intensity therapist support (Euro1951), followed by Featback with high-intensity therapist support (Euro2032), Featback without therapist support (Euro2102), and the waiting list (Euro2582). Featback seemed to be cost-effective as compared to the waiting list. No clear preference was found for Featback with or without therapist support. DiscussionA fully automated Internet-based intervention for ED symptoms with no, low-, or high-intensity therapist support represented good value for money when compared to a waiting list. This finding may have important implications for clinical practice, as both the unguided- and guided intervention could allow for more efficient care and widespread dissemination, potentially increasing the accessibility and availability of mental health care services for individuals with ED symptoms. (c) 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:1068-1076)