SUMMARYObjective: The objective of this (trial-based) economic evaluation was, from a societal perspective, to compare the cost-effectiveness of a multicomponent self-management intervention (MCI) with care as usual (CAU) in adult patients with epilepsy over a 12-month period. Methods: In a randomized-controlled trial, participants were randomized into intervention or CAU group. Adherence, self-efficacy (Epilepsy Self-Efficacy Scale [ESES]), quality-adjusted life years (QALYs), healthcare costs, production losses, and patient and family costs were assessed at baseline and during the 12-month study period. Incremental cost-effectiveness ratios (ICERs) (i.e., cost per increased adherence, selfefficacy, or QALY), and cost-effectiveness acceptability curves were calculated. Results: In total, 102 patients were included in the study, of whom 52 were in the intervention group. Adherence rates over 6 months were 63.7% for the CAU group and 75.9% for the intervention group. Adherence, ESES, and quality of life did not differ significantly between groups. An ICER of €54 per point increase in ESES score at 6 months and €1,105 per point increase at 12-month follow-up was found. The intervention resulted in an ICER of €88 per percentage of adherence increase at 6 months. ICERs of €8,272 and €15,144 per QALY gained were found at 6-and 12-month followup, respectively. Significance: Although no statistically significant difference was found after baseline adjustments, cost-effectiveness estimates for MCI appear promising. As rules of inference are arbitrary, it has been argued that decisions should be based only on the net benefits, irrespective of whether differences are statistically significant. Hence, the MCI may be a cost-effective addition to the current standard care for adults with epilepsy.